Method and device for parting glass substrate, liquid crystal panel, and liquid crystal panel manufacturing device

ABSTRACT

A method for cutting apart a glass substrate is provided whereby scribing of the glass substrate is possible without being affected by the presence or thickness of a deposited film formed thereon and without scratching the deposited film. To treat a glass substrate ( 1 ) having a deposited film ( 1   a ), such as a thin film or resin film, formed on one surface thereof, there are provided a shaving means ( 202 ), which is a blade that removes strip-shaped portions of the deposited film ( 1   a ) to expose strip-shaped regions on the glass substrate ( 1 ), and a wheel cutter ( 14   a ) that forms scribed lines along the strip-shaped regions exposed on the glass substrate ( 1 ). The glass substrate ( 1 ) is cut apart along the scribed lines.

TECHNICAL FIELD

The present invention relates to a method and an apparatus for cuttingapart a glass substrate, as used as a glass substrate of a liquidcrystal display element or the like, that has a deposited-film layer,such as a thin film or film layer, formed on at least one surfacethereof. The present invention relates also to a liquid crystal panelcomposed of a pair of substrate cells bonded together with liquidcrystal sealed in between and with polarizer plates bonded to the outersurfaces of the substrate cells, and to an apparatus for fabricating aplurality of such liquid crystal panels by cutting apart a glasssubstrate that has a plurality of pairs, arranged adjacent to oneanother, of glass substrate cells bonded together with liquid crystalsealed in between and that has polarizer plates bonded to both surfacesthereof.

BACKGROUND ART

Conventionally, a glass substrate is generally cut apart by so-calledscribing, specifically by first securing the glass substrate on aworkpiece stage of a cutting machine by vacuum chucking or the like,then forming a linear scratch called a scribed line, which actually is akind of crack (hereinafter referred to as a crack also), on one surfaceof the glass substrate by the use of a wheel-shaped cutter having theoutermost edge thereof formed of a superhard material, such as superhardalloy or diamond, and then pressing the glass substrate from behind theopposite surface thereof along the scribed line by the use of a pressingmeans, such as a press or roller, so that the crack that has been formedin the scribed line on the glass substrate in the directionperpendicular to the substrate surface develops until eventually theglass substrate breaks apart.

Today, liquid crystal display elements and other display devices similarthereto are fabricated, with a view to fabricating them at low costs, bycutting apart a large-format glass substrate material, having thinfilms, such as a transparent electrode like an ITO film, an insulatingfilm, an orientation film, and the like formed on the surface thereofbeforehand, into a shape having desired dimensions. When such a glasssubstrate having deposited-film layers (hereinafter referred to asdeposited films also) formed thereon is cut apart, various problemsarise that were unimaginable in the scribing of a conventional glasssubstrate. For example, scribing the film-deposited surface results indestroying the deposited films around the scribed lines. This makes thedeposited films scatter in the form of fine particles, and may lead tounacceptable product quality. Even scribing the opposite,non-film-deposited surface results in the deposited films beingscratched or deformed as a result of the film-deposited surface makingcontact with the stage of the cutting machine.

A solution to these inconveniences is proposed in Japanese PatentApplication Laid-Open No. H11-64834, which discloses a conventionalmethod for scribing a large-format glass substrate having depositedfilms formed thereon into strip-shaped sections having desireddimensions. This method attempts to overcome the above inconveniences byscribing the glass surface opposite to the film-deposited surface.

Now, with reference to FIG. 52, the method disclosed in Japanese PatentApplication Laid-Open No. H11-64834 will be described, mainly by quotingfrom its specification. A glass substrate 101 has a deposited film 102formed on one surface thereof. The glass substrate 101 is secured, withthe deposited film 102 up, on the top surface of a surface plate 103serving as a workpiece stage by an unillustrated chucking means, such asvacuum. In the surface plate 103, rectilinear openings 104 are formed atpredetermined intervals so as to permit a scribing means 105 serving asa crack-forming means for forming a scribed line, i.e., a crack, to movealong the openings 104 while scribing the bottom surface of the glasssubstrate 101. A pushing means 106 and a positioning means 107, eachrealized with an air cylinder or the like, work together to move theglass substrate 101 into one predetermined position after another. Thepushing means 106 has a pushing pin 110 provided at the tip thereof, andthe positioning means 107 has a positioning pin 111 provided at the tipthereof A pressing means 109 presses the glass substrate 101, from abovethe film-deposited surface thereof, against the top surface of thesurface plate 103 so as to hold the glass substrate 101 in position.

Next, how the method works will be described. When the surface plate 103is located in position “a” indicated with dotted lines, the glasssubstrate 101 is placed thereon by a unillustrated transporting machine,and then the positioning pin 111 at the tip of the positioning means 107swoops down on the surface of the surface plate 103 in response to apositioning signal from a unillustrated controlling means. Next, thepushing pin 110 at the tip of the pushing means 106 extends so as tomove the glass substrate 101 on the surface plate 103 in the directionindicated by a horizontal arrow in the figure until the glass substrate101 makes contact with the positioning pin 111. In this way, the placesat which to cut apart the glass substrate 101 are aligned with theopenings 104. Next, the controlling means gives instructions to chuckthe glass substrate 101 onto the surface plate 103, then move thepressing means 109 to the place where scribing is going to be performedand press it against the top surface of the glass substrate 101, andthen make the scribing means 105 scribe the bottom surface of the glasssubstrate 101. The scribing means 105 repeats scribing while travelingfrom one opening to another by being fed at the intervals at which toform scribed lines. Thus, according to this method, the glass substrate101 is scribed from below the bottom surface thereof through theopenings 104 formed in the surface plate 103. Here, the force with whichthe glass substrate 101 is chucked onto the surface plate 103 by thechucking means is not sufficient to counter the scribing load exerted bythe scribing means 105, and this insufficiency needs to be compensatedfor by pressing the glass substrate 101 from above the film-depositedsurface thereof with the pressing means 109.

The conventional method and apparatus for scribing (cutting-apart)described above are intended mainly for the cutting-apart of a glasssubstrate having a protective film formed on a large-format glassmaterial. With a glass substrate having a thin film, such as an ITOfilm, formed thereon, however, the use of a common pressing means, suchas the weight-shaped one 109 shown in FIG. 52, for countering thescribing load from below results in the thin film being destroyed by theload of the pressing means itself For further cost reduction of liquidcrystal display elements, attempts have been made to cut apart alarge-format glass material after forming films, such as a polarizerplate and a protective sheet, thereon instead of bonding those filmsafter the cutting-apart of the glass substrate as conventionallypracticed. It has been customary to bond polarizer plates to the outersurfaces of an upper and a lower glass substrate in the last step of theprocess of fabricating a liquid crystal cell. This, involvingpositioning of the films relative to the glass substrates and requiringan extra step, hampers cost reduction

The thickness of a deposited film varies according to its type; while athin film, such as an ITO film, is a few μm thick or thinner, a filmlayer, such as a polarizer plate, is 10 μm to 0.6 mm thick. With a glasssubstrate having such a film layer formed thereon, it is impossible todirectly scribe the film-deposited surface thereof. With theconventional method and apparatus for scribing described above, thepresence of the film layer makes it impossible to cut apart thesubstrate after scribing.

On the other hand, in the case of medium- to small-size liquid crystalpanels, in particular those with screen sizes up to about 5 inches, ithas been customary to fabricate them by first cutting apart large-formatglass substrates already bonded together roughly into strip-shaped glasssubstrates, then processing them in predetermined manners, as by puttingand sealing liquid crystal in between, then further cutting them apartfinely into a predetermined panel size to produce a plurality ofindividual cells, and then bonding polarizer plates to the individualcells to produce a plurality of liquid crystal panels.

Now, with reference to FIG. 53, the liquid crystal panel fabricated bythis conventional method will be described. In FIG. 53, there are shownperspective external views of the conventional liquid crystal panel,with the figure at (a) showing the top side thereof and the figure at(b) showing the bottom side thereof. This liquid crystal panel 550 iscomposed of a pair of substrate cells 551 a and 551 b bonded togetherand having liquid crystal sealed in between. One end of one 551 a of thesubstrate cells protrudes from one end of the other 551 b, and, on theinner surface of the protruding portion 551 aa are formed connectionterminals 553 by way of which the liquid crystal panel is driven.Moreover, on the outer surfaces of the substrate cells 551 a and 551 b,polarizer plates 552 a and 552 b are respectively bonded so as to coverthe display region (not shown). When the liquid crystal panel isdesigned for use in a so-called backlit liquid crystal display devicethat achieves display by transmitting light from a light source, thepolarizer plates 552 a and 552 b have roughly equal sizes and are soarranged as to face each other with the liquid crystal cells 551 a and551 b sandwiched in between.

The conventional method described above involves bonding polarizerplates one by one to individual cells, resulting in extremely poorfabrication efficiency. Even when a dedicated machine is used for thatpurpose, the influence of static electricity imposes a limit on the rateat which polarizer plates can be bonded (typically, 8 to 10 secondsrequired per polarizer plate). Thus, to cope with demands for highyields (fabrication of as many liquid crystal panels as possible) on themarket, a large number of polarizer plates need to be treatedconcurrently on a large number of machines. This greatly increasesplant-and-equipment spending, and thus increases the costs of liquidcrystal panels as end products.

A way to avoid this is proposed, for example, in Japanese PatentApplication Laid-Open No. H6-342139, which discloses a method forfabricating a liquid crystal panel whereby first a polarizer platehaving cut lines, marking where to cut apart, formed at predeterminedplaces thereon is bonded to a plastic substrate, and then the plasticsubstrate is cut apart along the cut lines to produce a plurality ofliquid crystal panels. According to this method, the polarizer plate isbonded to the substrate before the substrate is cut apart. This helpsgreatly scale down the step itself of bonding the polarizer plate. Thus,it is possible to improve fabrication efficiency without undulyincreasing plant-and-equipment spending.

This method, however, has the following disadvantages. First, apolarizer plate itself is formed of polyvinyl alcohol sandwiched betweenlayers of cellulose triacetate or coated with an acrylic resin, and isformed as a thin film about 0.2 to 0.6 mm thick. Therefore, when cutlines are formed in this polarizer plate, unexpected application of aload thereto may deform the portion thereof around the cut lines,eventually leading to warping or breakage of the polarizer plate. Inparticular, when bonded to a substrate, the polarizer plate needs to bebonded thereto so that the cut liens are located at predetermined placeson the substrate. This necessitates the use of a high-precision machine,which is disadvantageous to cost reduction of liquid crystal panels.

Second, when the substrate is cut apart, the polarizer plate is also cutapart (even where a cut line is formed, the portions of the polarizerplate across it are separated from each other). In particular when aglass substrate, which is brittle, is used as the substrate, thesubstrate and the polarizer plate have quite different properties, andtherefore, unless special care is taken, the glass substrate may breakat inappropriate places, or the polarizer plate may exfoliateunexpectedly. That is, it is extremely difficult to cut them apartwithout degradation in quality. Thus, this method leaves room forimprovement. Incidentally, Japanese Patent Application Laid-Open No.H6-342139 presupposes the use of a plastic substrate, of which thematerial is similar to the material of the polarizer, as the substrate,and therefore, quite naturally, it gives no special consideration to themethod for cutting them.

On the other hand, in the conventional liquid crystal panel shown inFIG. 53, the individual substrate cells 551 a and 551 b are thin (whenformed of glass, about 0.4 to 0.7 mm), and therefore the protrudingportion 551 aa, in particular, is mechanically weak. Thus, when theliquid crystal panel is transported from one place to another orassembled into a liquid crystal display device, if it is hit or dropped,the protruding portion 551 aa may be cracked or deformed, or broken at acorner. Accordingly, extremely cautions handling is required.

Moreover, in recent years, a polarizer plate itself has come to be givenmultiple functions, and is formed of a plurality of sheets havingvarious optical properties laid on one another. As a result, at theedges of a polarizer plate bonded to a substrate cell, there are oftenobserved burrs and the like. This makes it difficult to assemble aliquid crystal panel into a liquid crystal display device, or causes thepolarizer plate to exfoliate from the substrate cell unexpectedly.Furthermore, in a case where a removable protective film is laid on theouter surface of a polarizer plate so as to be integral therewith, whenthe liquid crystal panel is transported from one place to another orassembled into a liquid crystal display device, the film may exfoliatefrom the polarizer plate unexpectedly and scratch the polarizer plateitself

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide a method and anapparatus for cutting apart a glass substrate having a deposited-filmformed thereon whereby the glass substrate can be cut apart withoutbeing affected by the presence or the thickness of the deposited filmwith respect to the scribing of the glass substrate.

It is another object of the present invention to provide a liquidcrystal panel free from local weakening of mechanical strength and freefrom unexpected exfoliation of a polarizer plate. Simultaneously, it isalso an object of the present invention to provide an apparatus forfabricating a plurality of liquid crystal panels by cutting apart aglass substrate having a polarizer plate bonded thereto wherewith liquidcrystal panels as described above can be fabricated without degradationin quality and with improved fabrication efficiency.

To achieve the above objects, according to the present invention, in amethod of cutting apart a glass substrate having a deposited film formedthereon, there are provided glass substrate exposing means for removingstrip-shaped portions of the deposited film so as to expose strip-shapedregions on the substrate, and crack forming means for forming cracks soas to permit the glass substrate to be cut apart along the strip-shapedregions exposed thereon by the glass substrate exposing means. Here, theglass substrate is cut apart along the cracks. Moreover, according tothe present invention, in an apparatus for cutting apart a glasssubstrate, including a workpiece stage on which a glass substrate havinga deposited film formed thereon is placed, securing means for securingthe glass substrate in a predetermined position on the workpiece stage,crack forming means for forming cracks on the glass substrate so as topermit the glass substrate to be cut apart along the cracks, andactuating means for moving the crack forming means to a predeterminedposition, wherein the apparatus cuts apart the glass substrate into aplurality of blocks along the cracks, there is provided a glasssubstrate exposing means for removing strip-shaped portions of thedeposited film so as to expose strip-shaped regions on the glasssubstrate. Here, the cracks are so formed that the glass substrate iscut apart along the strip-shaped regions exposed thereon by the glasssubstrate exposing means.

By this method and with this apparatus, it is possible to removeportions of the deposited film sufficient to form cracks and then formcracks along strip-shaped regions exposed on the glass substrate topermit the glass substrate to be cut apart along the cracks. This makesit possible to cut apart a glass substrate having any type of depositedfilm formed thereon, from a thin film such as an overcoating film ortransparent electrode to a film such as a polarizer plate or a depositedfilm up to 1 to 2 mm thick such as a resin film or protective film,without being affected by the presence of the deposited film.

Moreover, to achieve the above objects, according to the presentinvention, a liquid crystal panel is composed of a pair of substratecells bonded together with liquid crystal sealed in between and withpolarizer plates bonded to outer surfaces of the substrate cells. Inaddition, one end of one of the substrate cells protrudes from one endof the other of the substrate cells so as to form a protruding portion,connection terminals by way of which the liquid crystal panel is drivenis formed on the inner surface of the protruding portion, and thepolarizing plate so extends as to cover the outer surface of theprotruding portion. Thus, the protruding portions is reinforced by thepolarizer plate. This enhances mechanical strength.

Moreover, according to the present invention, a liquid crystal panel iscomposed of a pair of substrate cells bonded together with liquidcrystal sealed in between and with polarizer plates bonded to outersurfaces of the substrate cells. In addition, the edges of the polarizerplates are so formed as to have a vertical section that becomes thinnerand thinner toward the substrate cells. This prevents the edges of thepolarizer plates from being caught accidentally, and thus helps preventexfoliation thereof.

Moreover, to achieve the above objects, according to the presentinvention, in an apparatus for fabricating a liquid crystal panel, morespecifically one for fabricating a plurality of the liquid crystal paneldescribed above by cutting apart a glass substrate that has a pluralityof pairs, arranged adjacent to one another, of glass substrate cellsbonded together with liquid crystal sealed in between and that haspolarizer plates bonded to both surfaces thereof, there are providedglass substrate exposing means for removing strip-shaped portions of thepolarizer plates so as to expose strip-shaped regions on the glasssubstrate, and crack forming means for forming cracks so as to permitthe glass substrate to be cut apart along the strip-shaped regionexposed thereon by the glass substrate exposing means. Here, the glasssubstrate is cut apart along the cracks. Thus, first, portions of thepolarizer plates are removed along the boundaries between the substratecells, then cracks for cutting-apart are formed along the strip-shapedregions exposed on the glass substrate as a result, and then the glasssubstrate is cut apart along the cracks. In this way, individualsubstrate cells are produced that each form a liquid crystal panel. Thatis, it is possible to cut apart the glass substrate without degradationin quality. Moreover, there is no need to use special equipment to bondthe polarizer plates on the glass substrate. This enhances fabricationefficiency.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically showing how a deposited film isremoved in the glass substrate cutting method of a first embodiment ofthe invention, with a side view shown at (a) and a front view shown at(b).

FIG. 2 is an enlarged view of FIG. 1(a).

FIG. 3 is a front view schematically showing how a crack (scribed line)is formed in the first embodiment.

FIG. 4 is a front view schematically illustrating how a deposited filmis removed in the cutting methods of a second and a third embodiment ofthe invention.

FIG. 5 is a diagram schematically illustrating how a deposited film isremoved in the cutting method of a fourth embodiment of the invention,with a side view shown at (a) and a front view shown at (b).

FIG. 6 a side view schematically showing another example of the fourthembodiment.

FIG. 7 is a front view schematically illustrating how a deposited filmis removed in the cutting method of a fifth embodiment of the invention.

FIG. 8 is a side view schematically illustrating how a deposited film isremoved in the cutting method of a sixth embodiment of the invention.

FIG. 9 is a front view schematically showing how a crack is formed inthe cutting method of a seventh embodiment of the invention.

FIG. 10 is an external view of the cutter used in the cutting method ofan eighth embodiment of the invention.

FIG. 11 is a side view schematically illustrating how a deposited filmis removed in the eighth embodiment;

FIG. 12 is a front detail view of the cutter used in the eighthembodiment;

FIG. 13 is a sectional view along line m-n shown in FIG. 12;

FIG. 14 is a front view of the glass substrate cutting apparatus of aninth embodiment of the invention;

FIG. 15 is a perspective view of the crack forming means (scribing unit)used in the cutting apparatus of the ninth embodiment;

FIG. 16 is a plan view of the cutting apparatuses of the ninth and atenth embodiment of the invention as seen from above;

FIG. 17 is a front view of the cutting apparatus of the ninthembodiment, in the state before deposited-film removal operation;

FIG. 18 is a front view of the cutting apparatus of the ninthembodiment, in the state in the middle of deposited-film removaloperation;

FIG. 19 is a diagram schematically illustrating the principles of theglass substrate cutting method of an eleventh embodiment of theinvention and how a part of a deposited film is removed by an apparatusemploying the method;

FIG. 20 is a diagram schematically illustrating the principles of theglass substrate cutting method of a twelfth embodiment of the inventionand how a part of a deposited film is removed and how a crack is formedby an apparatus employing the method;

FIG. 21 is a sectional view showing how parts of a deposited film areremoved in the glass substrate cutting method of a thirteenth embodimentof the invention;

FIG. 22 is a sectional view showing how cracks are formed in the cuttingmethod of the thirteenth embodiment;

FIG. 23 is a sectional view showing how parts of a deposited film areremoved and how cracks are formed in the cutting method of a fourteenthembodiment of the invention;

FIG. 24 is a perspective view showing the appearance of the liquidcrystal panel of a fifteenth embodiment of the invention;

FIG. 25 is a vertical sectional view of the liquid crystal panel of thefifteenth embodiment;

FIG. 26 is a diagram schematically showing how the properties of theliquid crystal panel of the fifteenth embodiment vary as the edge angleof the polarizer plate varies;

FIG. 27 is a perspective view schematically showing the appearance ofthe liquid crystal panel fabricating apparatus of a sixteenth embodimentof the invention;

FIG. 28 is an enlarged view of a principal portion of the glasssubstrate;

FIG. 29 is an external view of the wheel cutter for scribing;

FIG. 30 is a perspective view schematically showing the appearance ofthe liquid crystal panel fabricating apparatus of a seventeenthembodiment of the invention;

FIG. 31 is a perspective view schematically showing the appearance ofthe liquid crystal panel fabricating apparatus of an eighteenthembodiment of the invention;

FIG. 32 is an external perspective view showing examples of the bladeshape used in the liquid crystal panel fabricating apparatus of thethird embodiment;

FIG. 33 is a perspective view schematically showing the appearance ofthe liquid crystal panel fabricating apparatus of a nineteenthembodiment of the invention;

FIG. 34 is a perspective view schematically showing the appearance ofthe blade used in the liquid crystal panel fabricating apparatus of thenineteenth embodiment;

FIG. 35 is an exploded perspective view of the blade shown in FIG. 34;

FIG. 36 is a sectional view illustrating the operation of the liquidcrystal panel fabricating apparatus of the nineteenth embodiment;

FIG. 37 is a sectional view showing the blade used in the liquid crystalpanel fabricating apparatus of a twentieth embodiment of the invention;

FIG. 38 is a perspective view schematically showing the appearance ofthe liquid crystal panel fabricating apparatus of a twenty-firstembodiment of the invention;

FIG. 39 is an external view showing the blade used in the liquid crystalpanel fabricating apparatus of the twenty-first embodiment;

FIG. 40 is a perspective view showing the appearance of a glasssubstrate used as the material of a liquid crystal panel embodying theinvention;

FIG. 41 is a side view schematically showing an example of a liquidcrystal panel fabricating apparatus with respect to the glass substrateshown in FIG. 40;

FIG. 42 is a vertical sectional view of the glass substrate after beingtreated by the liquid crystal panel fabricating apparatus shown in FIG.41;

FIG. 43 is perspective view showing the appearance of the glasssubstrate after being treated by the liquid crystal panel fabricatingapparatus shown in FIG. 41;

FIG. 44 is a perspective view showing the liquid crystal panelfabricating apparatus of the invention running in the X direction;

FIG. 45 is a perspective view showing the liquid crystal panelfabricating apparatus of the invention running in the Y direction;

FIG. 46 is a vertical sectional view showing the liquid crystal panelfabricating apparatus of the invention running in the Y direction;

FIG. 47 is an external perspective view of a liquid crystal panelproduced by the operation of the liquid crystal panel fabricatingapparatus shown in FIGS. 44 to 46;

FIG. 48 is an external perspective view of the blade used in theoperation of the liquid crystal panel fabricating apparatus shown inFIGS. 44 to 46;

FIG. 49 is a perspective view showing the liquid crystal panelfabricating apparatus of the invention running in the X direction, as anexample of the preferred operation thereof;

FIG. 50 is a perspective view showing the liquid crystal panelfabricating apparatus shown in FIG. 49 now running in the Y directionafter running in the X direction;

FIG. 51 is a perspective view showing the liquid crystal panelfabricating apparatus shown in FIG. 50 now running in the X directionfor the second time after running in the Y direction;

FIG. 52 is a front view showing an example of a conventional glasssubstrate cutting apparatus; and

FIG. 53 is a perspective view showing the appearance of a conventionalliquid crystal panel.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, methods and apparatuses for cutting apart a glasssubstrate, liquid crystal panels, and method for fabricating a liquidcrystal panel, all embodying the present invention, will be describedone by one in detail with reference to the drawings. In the drawingsreferred to in the descriptions of the individual embodiments, suchcomponents as have the same functions among different embodiments areidentified with the same reference numerals as far as possible, andoverlapping explanations will not be repeated.

First, the glass substrate cutting method of a first embodiment of theinvention will be described. FIGS. 1 to 3 show the glass substratecutting method of the first embodiment. FIG. 1(a) is a side viewschematically showing how a deposited film formed on a glass substrateis removed, and FIG. 1(b) is a front view of FIG. 1(a) as seen from theleft thereof FIG. 2 illustrates in more detail the operation shown inFIG. 1, and FIG. 3 shows how a scribed line (crack) is formed on theglass substrate. Here, a deposited film may be any type of film, from athin film such as a overcoating film or electrode film to a thicker filmsuch as a polarizer plate, or a resin film or protective film.

In FIG. 1, reference numeral 1 represents a glass substrate having adeposited film 1 a formed thereon, reference numeral 2 represents ashaving cutter, like a wood chisel, serving as a glass substrateexposing means for cutting, shaving off, and thereby removingstrip-shaped portions of the deposited film 1 a so as to expose theglass substrate 1, and reference numeral 3 represents a workpiece stageon which the glass substrate is placed and secured. As shown in FIG.1(b), the shaving cutter 2 has a cross section that is substantiallyV-shaped with an opening angle θ. As the shaving cutter 2 is moved fromleft to right as seen in FIG. 1(a) parallel to the top surface of theglass substrate 1, with the cutting edge at the tip of the shavingcutter 2 pressed against the glass substrate 1 so as to make contactwith the bottom surface of the deposited film 1 a, i.e. the glasssurface of the glass substrate 1, the deposited film 1 a is cut, shaved,and thereby removed in the form of a waste strip 1 b as shown in FIG.1(a) that comes off along the substantially V-shaped groove of thecutting edge. The force with which the shaving cutter 2 is pressedagainst the glass substrate is adjusted according to the thickness andmaterial of the deposited film 1 a. Typically, the pressure is nothigher than 1 N (newton) for a deposited film, such as a resin film, ofup to a few tens of μm thick, but is equal to a few tens of N for a filmof about 0.5 mm thick.

In FIG. 1(a), the optimum angle α between the shaving cutter 2 and thesurface of the glass substrate 1 is adjusted according to the thicknessand material of the deposited film 1 a, and the shaving of the depositedfilm is performed with the optimum angle. The angle β between theshaving cutter 2 and its cutting edge is usually about 90°. Where thedeposited film 1 a is a thin film a few tens of μm thick, or a quitethick film layer, or in other situations, however, the angle β isadjusted according to the thickness and material of the deposited filmso that the shaving thereof is performed with optimum results.

FIG. 2 shows in more detail how the cutting and shaving of the depositedfilm 1 a is achieved by the shaving cutter 2 shown in FIG. 1(a). In itssimplest form, the shaving cutter 2 is formed as a blade like a V-shapedwood chisel by bending a plate-shaped material with a thickness t into asubstantially V-like shape with an opening angle θ as shown in FIG. 1(b)and then forming a clearance angle γ all along the cutting edge as shownin FIG. 2.

FIG. 3 shows how a scribed line (crack) 5 a is formed, in the shavedgroove 5 formed by the shaving cutter 2, by making a wheel-shapedscribing cutter 4 serving as a crack forming means roll along the shavedgroove while pressing it downward. The scribing means 4 serving as thecrack forming means has a cutter wheel 4 a, of which the edge is formedof diamond, superhard alloy, or the like, rotatably pivoted on a supportshaft 4 b. The edge angle of the wheel cutter 4 a is varied in the rangeof from about 60° to 140° according to the thickness and material of theglass substrate. Accordingly, the opening angle θ of the shaving cutter2 shown in FIG. 1(b) is determined in such a way as to permit the shavedgroove 5 to be so shaped and sized that the cutter wheel 4 a, whenforming the scribed line 5 a on the surface of the glass substrate 1,does not interfere with the deposited film 1 a or otherwise affectadversely.

FIG. 4(a) is a diagram showing the cutting method of a second embodimentof the invention. As compared with FIG. 1, which illustrates the firstembodiment, the shaving cutter 12 here has a different cross-sectionalshape. The second embodiment shown in FIG. 4(a) differs from the firstembodiment in that the cutting edge at the tip of the shaving cutter 12,where it makes contact with the surface of the glass substrate, has nota V-shaped opening but an arc-shaped opening with a radius R1 as shownin FIG. 4(a). The second embodiment, which is characterized by thearc-shaped cross section of the cutting edge of the shaving cutter 12,has, among others, the following advantages. It is possible to secure awider width at the bottom of the shaved groove 5 shown in FIG. 3, i.e.,a wider width in the exposed region (strip-shaped region) on the glasssubstrate, than in the first embodiment. This results in a greatermargin in the positioning of the edge of the cutter wheel 4 a. Moreover,the pressing force does not concentrate on one point at the cutting edgeof the shaving cutter as in the first embodiment. This helps maintainthe sharpness of the cutting edge of the shaving cutter 12 for a longerperiod. The radius R1 and the opening angle of the cutting edge are, asin the first embodiment, determined appropriately according to the edgeangle of the cutter wheel 4 a and the thickness of the deposited film 1a. In other respects, including how scribed lines are formed, the secondembodiment works in the same manner as the first embodiment, andtherefore overlapping explanations will not be repeated.

FIG. 4(b) shows the cutting method of a third embodiment of theinvention. In the third embodiment, the feature of the second embodimentis further developed. Specifically, here, the cross-sectional shape ofthe cutting edge at the tip of the shaving cutter 22 is composed of alinear portion with a width L1, which makes contact with the surface ofthe glass substrate 1, and slanted portions with an opening angle θ1,which cut the deposited film 1 a. Where the linear portion meets theslanted portions, they are connected together by two small arcs r2. Thishelps perform the cutting and shaving of the deposited film 1 a withsatisfactory results, and also helps prolong the working life of thecutting edge of the shaving cutting 22. As compared with the secondembodiment, the third embodiment, in which the width at the bottom ofthe shaved groove 5 is determined by L1, permits easier setting of thedimensions of the shaved groove. As in the second embodiment, the shapeand dimensions of the cutting edge, specifically the values of L1 andθ1, are determined appropriately according to the edge angle of thecutter wheel 4 a and the thickness of the deposited film 1 a. In otherrespects, including how scribed lines are formed, the third embodimentworks in the same manner as the first embodiment, and thereforeoverlapping explanations will not be repeated.

FIGS. 5 and 6 show the cutting method of a fourth embodiment of theinvention. FIG. 5(a) is a side view showing how a deposited film 1 aformed on the glass substrate 1 is cut by two flat-plate-shaped cutters32 and 32′ arranged so as to face each other in the fourth embodiment,and FIG. 5(b) is a front view of the FIG. 5(a) as seen from thedirection indicated by an arrow therein. In this embodiment, to bringthe edge of a cutter wheel 4 a into contact with the glass surface of aglass substrate 1 when it is scribed, a shaved groove is formed in thedeposited film 1 a by moving two cutters, arranged substantiallyparallel to each other and kept in contact with the deposited film 1 a,in the direction indicated by an arrow in FIG. 5(a) so as to cut thedeposited film 1 a. For example, the two cutters 32 and 32′ are formedso as to have a side shape as shown in FIG. 5(a), are arranged with acutting angle ε appropriately determined in the range of, for example,from 20° to 50° according to the thickness and material of the depositedfilm 1 a, and are moved parallel to the glass substrate 1 as indicatedby the arrow while being pressed against it so as to cut the depositedfilm 1 a. As shown in FIG. 5(b), as in the third embodiment, theinterval L2 and the inclination angle θ2 between the two cutters 32 and32′ are so determined that the edge of the cutter wheel, when scribingthe glass substrate 1, does not interfere with the deposited film 1 a.

In the fourth embodiment, even after the deposited film 1 a is cut bythe two flat-plate-shaped cutters 32 and 32′, the deposited film 1 aremains in the form of a waste strip 1 b as shown in FIG. 5(b), andtherefore this waste strip 1 b needs to be shaved off and removed in adownstream step. This is achieved, for example, by shaving off andremoving it with a shaving cutter, as the one shown in FIG. 4(b), havinga trapezoidal or C-shaped cross section and having a bottom width L1equal to or slightly smaller than L2 shown in FIG. 5(b). In the fourthembodiment, cutting and shaving are performed in different steps. This,however, makes it possible to cut the deposited film 1 a more sharplythan in the first to third embodiments. Thus, even a deposited film asthick as 1 to 2 mm can be cut with satisfactory quality in cut surfaces.Moreover, it is possible to purchase the cutter cheaply by using awell-known, commercially available cutter blade 32 b as shown in FIG. 6.

FIG. 7 shows the cutting method of a fifth embodiment of the invention.This embodiment is a further developed version of the fourth embodiment.Specifically, how cutting, shaving, and scribing are performed in thisembodiment is the same as in the fourth embodiment except that a cutter42 as shown in FIG. 7 is used instead of the cutter 32 shown in FIG. 5.Accordingly, a left or right side view of FIG. 7 is identical with FIG.5(b), and is therefore omitted. Whereas in the first to fourthembodiments the cutter permits the cutting and shaving of the depositedfilm 1 a only in one direction, i.e., in the direction in which thecutter moves, in this embodiment the cutter 42 is given a side shape asshown in FIG. 7 so as to permit cutting also in the leftward andrightward directions as seen in FIG. 7 without requiring a change in thearrangement of the cutter when the cutting direction is changed. Thecutting angles ε1 and ε2 of the cutter 42 are so determined as to offerthe optimum cutting conditions that fit the thickness and material ofthe deposited film 1 a. When the cutter 42 is used to cut in bothdirections, the cutting angles ε1 and ε2 are usually set equal to eachother. The shaving and removal of the waste strip 1 b is performedseparately in the leftward and rightward directions in a manner similarto that used in the fourth embodiment.

FIG. 8 shows the cutting method of a sixth embodiment of the invention.In this embodiment, a shaving cutter 52 composed of a cutter blade 52 aand a holder portion 52 b is used. Any of the cutters used to cut andshave the deposited film 1 a in the cutting methods of the first tofifth embodiments described above may be adapted to the cutter blade 52a of this embodiment. The holder portion 52 b serves as a handle thatholds the cutter blade 52 a when the deposited film 1 a is cut andshaved. In addition, by unifying and standardizing the length and thecross-sectional shape of the holder portion 52 b, for example into arectangular shape having predetermined dimensions, it is possible, wherea deposited film is cut and shaved with the shaving cutter 52 fixed to ajig or machine, to use any of the cutters of the first to fifthembodiments by interchanging them on a single jig or machine.

The holder portion 52 b is formed preferably of an appropriately elasticmaterial, for example resin such as Duracon or Delrin, or more flexiblerubber such as silicone rubber or nitrile rubber, or, in some cases,wood. By so doing, even if there are variations or the like in thethickness or hardness of the deposited film to be shaved, the elasticityof the holder portion 52 b absorbs variations in the resistance tocutting and shaving. This can be used as a safety mechanism in a cuttingapparatus to which the techniques of this embodiment are applied. Theshaving cutter 52 may be given elasticity by exploiting the action ofcoil springs 77 a and 77 b (see FIGS. 15 and 17), which will bedescribed later in connection with a ninth embodiment.

The blade of the cutter used to cut and shave the deposited film 1 a inthe first to sixth embodiments is formed of a common material, such ascarbon tool steel or martensitic stainless steel, hardened by heattreatment or the like as required. However, there is no restriction onthe material of the cutter so long as it can appropriately cut and shavevarious deposited films 1 a made of different materials and havingdifferent thicknesses. Moreover, the cutter used to cut and shave thedeposited film 1 a in this embodiment has its cross-sectional shape,such as shown in connection with the first to fifth embodiments, formedalong an extended length. This makes it possible to grind the cuttingedge again and again and use the blade for a longer period.

FIG. 9 shows the cutting method of a seventh embodiment of theinvention. In the cutting method of this embodiment, in an upstream stepprior to scribing, the deposited film 1 a is shaved and removed in thesame manner as in one of the first to sixth embodiments described above.Specifically, in the first to sixth embodiments, as shown in FIG. 3, thedeposited film 1 a is cut, shaved, and removed so as to form a shavedgroove 5 in the deposited film 1 a, and then a scribing means is made toroll along the bottom 1 c of the shaved groove 5, i.e. along astrip-shaped region on the glass substrate 1, while pressing it so as toform a scribed line 5 a. In the seventh embodiment, the glass substrateis cut apart by scribing the surface thereof opposite to thefilm-deposited surface thereof.

As shown in FIG. 9, the glass substrate 1 is secured on the workpiecestage 3 by an unillustrated securing means such as vacuum chucking. Inthe workpiece stage 3, an elongate opening 3 a is formed to permit thescribing means 4 to scribe the bottom surface of the glass substrate 1.In this embodiment, a scribed line 5 c is formed on the bottom surfaceof the glass substrate 1, right below the bottom 1 c of the shavedgroove 5 formed on the top surface of the glass substrate 1 by one ofthe methods described in connection with the first to sixth embodiments.

In the glass substrate cutting step following the scribing step, apressing force is applied to the surface opposite to that on which thescribed line is formed so that the crack in the scribed line developsuntil the glass substrate breaks apart. In methods in which scribing isperformed on the bottom 1 c of the shaved groove 5 formed in thedeposited film 1 a, in the cutting step following the scribing step, itis necessary to apply a pressing force and cut the glass substrate frombelow the surface thereof opposite to the scribed surface. Thus, forexample, in methods in which the scribed surface, i.e., thefilm-deposited surface, of the glass substrate is placed directly on thesurface plate and a load is applied thereto from above by a press orroller, the pressing force applied to cut apart the glass substrate maydestroy or deform the deposited film layer placed directly on theworkpiece stage. By contrast, in the cutting method of the seventhembodiment, a pressing force exerted by a plate-shaped pressing jig or aroller adapted to the shape and dimensions of the shaved groove 5 can beapplied in the direction indicated by an arrow B so as to concentrate onthe bottom 1 c of the shaved groove 1 c shown in FIG. 9. This permitsthe scribed line 5 c to develop vertically to achieve cutting. Thus, itis possible to cut apart the glass substrate without pressing ortouching the deposited film 1 a.

FIGS. 10 to 13 show the cutting method of an eighth embodiment of theinvention. This embodiment is devised to achieve satisfactory shavingand removal of a deposited film before scribing when dealing with aglass substrate having a relatively thick deposited film, about 0.05 mmto 2 mm thick, typically such as a resin film, formed thereon. Here, theadvantages of the shaving cutters used in the first and secondembodiments are combined together; specifically, the shape of thecutting edge used in the first or second embodiment is formed out of around-bar-shaped material. This permits the deposited film to be shavedwith better results.

FIG. 10 shows a front view and a side view of the shaving cutter 62 usedin this embodiment. A round-bar-shaped material, such as superhard alloyor carbon tool steel, is formed into the shape of the shaving cutter.The external diameter d1 of the round-bar-shaped material is determinedappropriately according to the thickness of the deposited film to beshaved, and is typically 5 to 10 mm. The symbol F represents a flatholder portion that is formed by cutting away a portion of thecircumference d1 parallel thereto as shown in FIG. 10. The holderportion serves as a reference surface relative to which other portionsare formed, and also serves a function similar to that of the holderportion 52 b shown in FIG. 8. The total length L3 of the shaving cutter62 is so determined as to fit the member by which it is held and theapparatus on which it is used, and is set equal to 35 mm in thisembodiment. As shown in the front view of FIG. 10, a shaving bladehaving a substantially V-shaped cross section with an opening angle ofOn is formed from an end surface of the shaving cutter 62 over a lengthL4. The value of On will be discussed in detail later. The blade lengthL4 is determined in the range of from 5 to 10 mm according to thematerial and thickness of the deposited film to be shaved, and is setequal to 7 mm in this embodiment. The portion of the blade groovelocated on the right of the portion “i” shown in the figure is formed asan arc-shaped groove with a mild curve R3, and serves to smoothly ejectthe linear waste strip 1 b that has been shaved off. In this embodiment,R3 is set equal to 38 mm. The curve R4 of the bottom of the blade havinga V-shaped cross section is determined in the range from about 0.5 to 1mm according to the material and thickness of the deposited film and thedimensions of the scribing cutter. In this embodiment, R4 is set equalto 0.5 mm. The cutting edge needs to be designed to shave and remove thedeposited film completely, and is therefore so formed as to have tipangles θ7 and θ8 in two stages. In FIGS. 10 and 13, t1 represents thedistance from the cutting edge to the boundary between θ7 and θ8. Thedetails are shown in a view seen from the direction C in FIG. 12. Inthis embodiment, t1 is set equal to 0.3 mm, θ7 is set equal to 30°, andθ8 is set equal to 40°. By setting t1 equal to as small as about 0.3 mm,it is possible to set the effective tip angle θ7 relatively small, i.e.,equal to 30°, to achieve satisfactory shaving performance while settingthe tip angle θ8 in the cutting edge portion t1 equal to 40° to securesufficient mechanical strength at the cutting edge of the shaving cutter62.

Next, the workings of the eighth embodiment will be described with thefocus placed on what is illustrated in the figures. FIG. 11 shows how adeposited film 1 a formed on a glass substrate 1 is shaved and removedby a shaving cutter 62. The angle θ9 at which the shaving cutter isarranged relative to the glass substrate corresponds to the rake anglewith which cutting and shaving are performed, and is determinedappropriately in the range of from 35° to 45° according to the thicknessand material of the deposited film. In this embodiment, when this anglewas set equal to 43°, a 1 mm-thick rubber-based deposited film was cutand shaved with satisfactory results. FIG. 11 shows how the shavingcutter 62, while moving in the direction H, cuts and shaves thedeposited film 1 a. The waste strip 1 b shaved off is smoothly ejectedalong an arc-shaped groove marked as G in FIG. 10. The pressing forcewith which the shaving cutter 62 is pressed vertically downward againstthe surface of the glass substrate 1 is about 1 to 40 N. A strongerpressing force produces a scratch on the glass surface below thedeposited film, which adversely affects scribing.

Now, a description will be given of On shown in FIG. 10 with referenceto FIG. 12, which is an enlarged front view of the shaving cutter 62.The opening angle θ3 formed by the cutting edge of the shaving cutter 62is determined in the range of from 50° to 140° according to the tipangle of the scribing cutter. The opening angle θ4 measured at adistance of 3 to 10 mm from the cutting edge is made smaller than θ3 byan angle in the range of from 3° to 6°. The purpose and advantage ofmaking θ4 smaller than θ3 will be described with reference to FIG. 13.FIG. 13 is a sectional view of the cutting edge of the shaving cutter 62shown in FIG. 12, taken along line m-n, as seen from above. With θ4smaller than θ3, when the shaving cutter 62 moves in the direction K tocut and shave the deposited film 1 a, it forms an angle δ2 relative tothe cutting direction. The presence of this angle δ2 serves to increasewhat is called the shear angle in the theory of cutting, and therebypermits the deposited film to be cut and shaved with better results. Inexperiments, a 1 mm-thick resin deposited film was cut and shaved withfar higher cutting/shaving workability and cutting quality than when noδ2 was present, i.e., when θ3 and θ4 were set equal. In this embodiment,for example, when θ4 was set equal to 80° and θ3 was set equal to 84°,i.e., with θ4 smaller than θ3 by 4°, the deposited film was cut with thebest results, and, as describe above, almost comparably satisfactorycutting quality was obtained when θ4 was made smaller than θ3 by anangle in the range of from 3° to 6°. The improvement of cutting qualityachieved by making the opening angle θ4, at a distance from the tip ofthe shaving cutter, smaller than the opening angle θ3, at the tip of theshaving cutter, was observed markedly with a resin or rubber-baseddeposited film 0.5 mm or more thick.

In FIG. 10, δ1 indicates that the cutting edge is not perpendicular tothe circumference of the shaving cutter 62, but is slightly inclinedinward from top to bottom as seen in the figure. This means that makingθ3 smaller than θ4 results in producing δ1. On the other hand, in FIG.12, θ5 and θ6 are shown in a sectional view of and around the cuttingedge as seen from the direction C. This means that, for example, when θ3is set equal to 84° and θ4 is set equal to 80°, even if θ7 is set equalto 30° and θ8 is set equal to 40° in FIGS. 10 and 12, θ5 is equal toabout 22° and 06 is equal to about 31°.

As described earlier, the shaving cutter 62 is produced by forming aheat-treatable material such as superhard alloy or carbon tool steelinto its shape and then subjecting it to heat treatment either only atthe cutting edge or in entirety. The eighth embodiment is characterizedby the shape of the shaving cutter used to shave the deposited film andby how it is shaved, and the scribing step following the shaving step isperformed by the method exemplified by the first embodiment or themethod of the seventh embodiment.

Next, as a ninth embodiment of the invention, a cutting apparatusemploying the cutting methods of the first to eighth embodiments will bedescribed. FIG. 14 is a diagram illustrating the front face of thecutting apparatus employing the cutting methods of the first to eighthembodiments. Reference numeral 66 represents a scribing unit that has ascribing cutter and/or a shaving cutter provided at the bottom. Thescribing unit 66 moves the scribing cutter and the shaving cutter fromside to side as seen in the figure along a guide rail 67 composed of awell-known ball slide or the like while pressing them with apredetermined load against a glass substrate 1 by the use of anunillustrated well-known pressing means exploiting hydraulic pressure,compressed air pressure, the resilience of a spring, or the like. In theexample shown in FIG. 14, part of the scribing unit 66 is fixed to atiming belt 65. As an unillustrated driving means such as a motorrotates a pulley 64, the timing belt 65, passed around the pulley 64,travels a desired distance along the guide rail 67. In the diagram, thescribing unit 66 is driven by the timing belt; however, it may be drivenby a combination of an well-known actuating means such as a ball screwand a motor and a controller that drive it.

A chassis 60, a workpiece stage 63, and a support stand 63 a are formedintegrally. In the workpiece stage 63, suction holes are formedvertically at appropriate places to permit the glass substrate 1 to besecured on the top surface of the workpiece stage 63 by an unillustratedsecuring means such as vacuum chucking. The workpiece stage 63 and thesupport stand 63 a are rotatable through 90° as seen from above or belowFIG. 14 by the action of a rotating means housed inside the chassis 60.A C-shaped movable block 200 strides over the top face of the chassis60, and is moved frontward or backward as seen in the figure over adesired distance at a time relative to the chassis 60 by anunillustrated driving means such as a motor and an unillustratedcontrolling means. As described above, in the cutting apparatus of thisembodiment, the sliding movement of the scribing unit 66 and the 90°rotation of the workpiece stage 63 permit the glass substrate 1 to bescribed in the X and Y directions, i.e., in a grid-like pattern.

FIG. 15 is a diagram showing in detail the structure of the scribingunit 66 shown in FIG. 14. A unit base plate 71 engages with the timingbelt 65 and the guide rail 67 shown in FIG. 14 to permit the entirescribing unit 66 to slide. A joint 74 joins the unit base plate 71 to ascribing base plate 75. The rear portion 74 b of the joint 74 is fixedintegrally to the unit base plate 71 with screws or the like put throughthe unit base plate 71 from behind it. The front portion 74 a and therear portion 74 b of the joint 74, together with the scribing base plate75 fixed integrally to the front portion 74 a, can slide up and down bythe action of a sliding means such as a dovetail joint as shown in thefigure or a well-known sliding means such as a ball slide. The frontportion 74 a of the joint 74 and the scribing base plate 75 joinedintegrally thereto are kept pulled upward relative to the unit baseplate 71 all the time by the tension exerted by unillustrated coilsprings. The upward tension is stopped by the tip of a micrometer screw72 fixed through a micrometer fitting block 73 to the unit base plate71. The micrometer screw 72 is used to fine-adjust and appropriately setthe vertical position of the entire unit including the scribing baseplate 75 and the vertical position of the tip of the shaving means andthe scribing means described later.

On the scribing base plate 75, there are supported a shaving block 81and a scribing block 82, both substantially L-shaped, so as to becoaxially rotatable about a rotation shaft 83. On the scribing baseplate 75, there is fixed a support block 76, with which adjustmentscrews 76 a and 76 b are screw-engaged, each having a hook formed at thetip. From these hooks, coil springs 77 a and 77 b are stretched tospring end screws 78 a and 78 b that are screwed into the top of theshaving block 81 and the scribing block 82, respectively. In thisstructure, the shaving block 81 and the scribing block 82 are all thetime loaded with a force that tends to rotate them counter-clockwiseabout the rotation shaft 83 as seen from the front right-hand side ofFIG. 15. That is, the shaving means 202 and the scribing means 14 arepressed downward all the time. This counter-clockwise rotation isstopped by contact between the tips of stopper screws 80 a and 80 bscrew-engaged with the vertical arm portions of the shaving block 81 andthe scribing block 82 and tips 79 a and 79 b formed on astopper/pressing means 79 fixed to the scribing base plate 75. While theshaving means 202 is pressed downward with a pressing force of about 10to 20 N, the scribing means 14 is pressed downward with a pressing forceof about 1 to 40 N; that is, they are pressed downward with differentpressing forces. Therefore, the coil springs 77 a and 77 b areindividually set at tensions that produce appropriate loads for them.The tensions are fine-adjusted by screwing the adjustment screws 76 aand 76 b into and out of the support block 76. A deposited film surfacedetecting means 84, by extending a spindle integral with a detectorfitted at the tip thereof and by the use of a well-known electricaldetecting means such as a linear scale or differential transformer,detects the vertical position of the deposited film formed on the glasssubstrate as an electric signal by way of an unillustrated signal cable.The tip 84 a of the detecting means 84 for detecting the deposited filmsurface is formed as a roller made of resin such as nylon or Teflon (R),and the detector operates with a sensing force as low as 0.2 N (newton)or lower so as not to scratch or deform the surface of the depositedfilm 1 a. FIG. 16(a) is a plan view showing the main components shown inFIG. 15, such as the shaving block 81, the scribing block 82, theshaving means 202 serving as a glass substrate exposing means, thescribing means 14, and the deposited film surface detecting means 84, asseen from above. This figure shows that, as the result of the depositedfilm detecting means 84, the shaving means 202, and the scribing means14 being arranged in a row, it is possible to shave the deposited film 1a and scribe the top surface of the glass substrate 1 simultaneously asthe scribing unit 66 is moved along one path.

Next, the operation and workings of the cutting apparatus of a ninthembodiment of the invention will be described. FIG. 17 is a front viewshowing the cutting apparatus of FIG. 14 in a state in which thescribing unit 66 is located in the leftmost, stand-by position, i.e.,the detecting tip 84 a of the deposited film surface detecting means 84,the shaving means 202, and the scribing means 14 are all located awayfrom the top surface of the glass substrate 1. In this state, theshaving block 81 and the scribing block 82 are loaded with a force thattends to rotate them counter-clockwise about the rotation shaft 83 bythe tension of the coil springs 77 a and 77 b, but thiscounter-clockwise rotation is stopped by the tips of the stopper screws80 a and 80 b making contact with the tips 79 a and 79 b of thestopper/pressing means 79, and thus the shaving block 81 and thescribing block 82 remain at rest. The cutting apparatus operates asfollows. First, in response to the first movement command signal, thescribing unit 66 moves in the direction indicated by an arrow M in FIG.17. As the shaving block 81 moves rightward, the detecting tip 84 a ofthe deposited film surface detecting means 84 runs onto the glasssubstrate 1 and detects the position of the surface of the depositedfilm 1 a. Then, the air cylinder provided in the stopper/pressing means79 extends, and its tip 79 a presses the stopper screw 80 to apredetermined degree so that the tip of the shaving means 202 is socontrolled as to reach the glass surface on the basis of the thicknessof the deposited film 1 a on the glass substrate 1 as correctedaccording to the result of detection by the detecting means 84. When thescribing unit 66 moves over a distance L5 shown in FIG. 17, the shavingmeans 202 starts cutting and shaving the deposited film 1 a. When thescribing unit 66 further moves and completes a distance L6 shown in FIG.17, the cutter wheel 14 a at the tip of the scribing means 14 runs ontothe top surface of the glass substrate 1 where the deposited film 1 ahas been shaved off. The scribing block 82 is loaded with a force thattends to rotate it counter-clockwise by the tension of the coil spring77 b, and thus the cutter wheel 14 a exerts, at its tip, a predeterminedpressing force acting downward. This pressing force permits scribing ofthe top surface of the glass substrate 1. FIG. 18 shows how the shavingmeans 202 shaves the deposited film 1 a and how the scribing means 14scribes the top surface of the exposed glass substrate 1 where thedeposited film 1 a has been shaved off. As described earlier, the cutterwheel 14 a at the tip of the scribing means 14 is formed as a rollerlike the tip of the detecting means 84 a, and does not require thedetection of the surface position of the glass substrate 1 or theadjustment of the vertical position of the tip of the cutting wheel 14 aas does the shaving means 202. Thus, scribing of the top surface of theglass substrate 1 is achieved simply by moving the cutter wheel 14 a,formed as a roller, while pressing it downward. Accordingly, in thestate shown in FIG. 18, the tip 79 b of the stopper/pressing means 79for rotating the scribing block 82 clockwise is not operating.

In FIGS. 17 and 18, there is shown an example of a dust removing means85. The dust removing means 85 is a hose made of soft resin or rubber,and is flexibly movable together with the scribing unit 66. The dustremoving means 85 has its opening located near the shaving means 202 andthe scribing means 14, and serves to remove particulate dust producedduring shaving and scribing by the use of a negative pressure supplyingmeans such as vacuum. Depending on the particle size and the amount ofparticulate dust produced, a positive pressure supplying means such assprayed air may be used instead. The deposited film that has been shavedoff can be removed by a removing means, like G shown in FIG. 10,provided in the shaving means 202. For the removal of fine shavings, abrush-like remover may be provided immediately behind the shaving means202.

In FIG. 18, when the scribing unit 66 further moves until the detectingtip 84 a of the detecting means 84 falls below the surface position ofthe deposited film 1 a, a signal indicating the end of the scribing stepis generated. From this time point, the scribing unit 66 further movesover a distance longer than the distance between the detecting tip 84 aand the tip of the shaving means 202, i.e., the dimension L5 shown inFIG. 17. After completion of shaving, the tip 79 a of thestopper/pressing means 79 further extends its air cylinder under thecontrol of an unillustrated controlling means so that the shaving means202 is moved upward, away from the surface of the glass substrate 1. Thescribing means 14 needs to be controlled in a similar manner. As withthe shaving means, the scribing means 14 may be released upward afterthe scribing unit 66 has moved over a distance corresponding to thedistance L6 between the detecting tip 84 a and the cutter wheel 14 ashown in FIG. 17. However, the tip 79 b of the stopper/pressing means 79is kept away from the tip of the stopper screw 80 b during scribing, andthe tip 79 b makes contact with the tip of the stopper screw 80 b underthe tension of the coil spring 77 b as soon as the cutter wheel 14 afalls below the top surface of the glass substrate 1 on completion ofscribing. Thus, this may be used to turn on an electric contact toextend an air cylinder and thereby release the scribing means 14 toabove the glass substrate. The latter method is technically simpler.After, in this way, the deposited film 1 a is shaved and the surface ofthe glass substrate 1 is scribed where the deposited film 1 a has beenshaved, the scribing unit 66 is moved back to the stand-by position withthe shaving means 202 and the scribing means 14 lifted up so as not tointerfere with the glass substrate. Thereafter, as the movable block 200described with reference to FIG. 14 is moved frontward or backward overa desired distance at a time, shaving and scribing are repeated. In thisway, the glass substrate having a deposited film formed thereon can bescribed into strip-shaped sections arranged at desired intervals. Then,the workpiece stage 63 described with reference to FIG. 14 is rotatedthrough 90° and similar steps are performed to scribe the film-depositedglass substrate into a grid-like pattern.

The shaving of the deposited film in a grid-like pattern from afilm-deposited glass substrate and the scribing thereof in a grid-likepattern can be achieved also by exploiting the facts, described earlierwith reference to FIG. 14, that the scribing unit 66 moves from side toside, as seen in FIG. 14, and that the movable block 200 moves back andforth, as seen in FIG. 14. The workpiece stage 63 may be so structuredas to move back and forth as seen in FIG. 14. In that case, the scribingmeans and the shaving means fitted at the bottom of the scribing unit 66shown in FIG. 14 needs to be so structured as to be integrally rotatablethrough 90° relative to the glass substrate surface. Specifically, astructure like that of the movable unit 410 shown in FIG. 41, whichshows the eighteenth to twenty-first embodiments described later, isadopted. In the movable unit 410 shown in FIG. 41, reference numeral 430represents a combination of two wheel cutters arranged so as to faceeach other for cutting a polarizer plate. By adopting this integratedstructure, with the two wheel cutters replaced with a single cutterwheel for scribing, and with 460 replaced with a shaving means, it ispossible to add the above-mentioned capability of 90° rotation.Furthermore, by adding the capability of 180° rotation, it is possibleto remove the deposited film and scribe in both of the X and Ydirections.

The shaving means 202 and the scribing means 14 start and stop shavingand scribing, respectively, with different timing. When, after shavingand scribing are complete, the scribing unit 66 returns to the stand-byposition, the shaving means 202 and the scribing means 14 need to bereleased by being lifted up so as not to make contact or interfere withthe glass substrate. Thus, the air cylinder that is provided in thestopper/pressing means 79 and of which the degree and timing ofextension are controlled by an unillustrated controller needs to beprovided separately at two different places to individually actuate thetip 79 a for the shaving block and the tip 79 b for the scribing block.In the ninth embodiment, as shown in FIG. 18, the shaving means 202 hasthe shaving cutter described in connection with the first embodimentfixed to the shaving block with cutter fitting screws 86. However, anyof the shaving cutters used in the cutting methods described inconnection with the first to sixth and eighth embodiments may be appliedto the cutting apparatus of this embodiment. When the deposited film 1 ais shaved, the tip of the shaving means 202 needs to be accuratelypositioned at the surface of the glass substrate 1. The verticalposition of each tip can be set appropriately by screwing in or out thecorresponding one of the stopper screws 80 a or 80 b. The verticalposition of the tip of the shaving means 202 requires the finestpositioning, and this tip needs to be positioned at the top surface ofthe glass substrate 1 immediately before the shaving step is started.Ultimately, the position of the tip is adjusted accurately by adjustingthe micrometer screw 72. After the stopper screw 80 has been screwed inand out for adjustment, it is fixed with a nut 203. Moreover, in theninth embodiment, as shown in FIG. 18, the shaving means 202 is fixed bybeing screwed into a groove formed in the shaving block 81. However, thecutting angle of the shaving means relative to the glass substratesurface may be made adjustable. Specifically, though not illustrated,this is achieved by separating the horizontal arm portion of the shavingblock 81 so that its portion somewhat closer to the shaving means 202than its own center is loosely fixed so as to be rotatable about arotation shaft, and providing a mechanism that permits this portion tobe clamped with a clamping means after the angle with which the shavingmeans 202 shaves the deposited film 1 a is adjusted to the optimumangle.

Next, the cutting apparatus of a tenth embodiment of the invention willbe described. In the ninth embodiment, as shown in FIG. 16(a), theshaving means 202 and the scribing means 14 are arranged in a row withrespect to the direction in which the scribing unit moves, so thatshaving of the deposited film and scribing are performed simultaneouslyas the scribing unit is moved along one path. In the tenth embodiment,the shaving means 202 and the scribing means 14 are arranged at aninterval equal to the intervals at which scribing is performed to formstrip-shaped sections. FIG. 16(b) shows the positional relationshipbetween the shaving block 81′ and the scribing block 82′ as seen in aplan view in this embodiment. If it is assumed that the scribing unitmoves in the direction indicated by an arrow in FIG. 16(b) as scribingis performed to form strip-shaped sections, then the shaving block 81′needs to be disposed at the front in the movement direction so that theshaving step is performed first. The interval S1 between the shavingmeans 202 and the scribing means 14 is adjusted, as by adjusting thethickness of a spacer 204, to the intervals, i.e., the pitch, at whichscribing is performed to form strip-shaped sections. Thus, thisembodiment is the same as the ninth embodiment in that both shaving ofthe deposited film and scribing are performed as the scribing unit ismoved along one path, but is different therefrom in that the scribingunit moves across a distance corresponding to the pitch to a groovewhere the shaving of the deposited film is already complete and thenperforms scribing along that groove. When a large-format glass substrateis scribed at a predetermined pitch, this embodiment requires thescribing unit to be moved two more times than does the ninth embodiment.However, as compared with the ninth embodiment, here, it is notnecessary to extend the cutting apparatus in the direction in which thescribing unit moves, and this helps make the cutting apparatus compactin its width direction. Moreover, it is possible to dispose anappropriate waste shaving removing means with ample space at the rear inthe movement direction of the shaving means 202, and this helpsalleviate the effects of waste shavings that are left in the shavedgrooves during scribing. In other respects, the cutting apparatus ofthis embodiment has basically the same structure as that of the ninthembodiment, and therefore overlapping explanations will not be repeated.

The glass substrate cutting method and apparatus of an eleventhembodiment of the invention will be described below with reference toFIG. 19. In the ninth embodiment, a detecting means for detecting anelectric signal, which serves as a means for positioning the tip of theshaving cutter accurately at the top surface of the glass substrate atthe start of the shaving step, is provided at the front of the shavingmeans in order to detect the position of the top surface of thedeposited film, then correct the thickness of the deposited film by acontrolling means such as programmable control, and then position thetip of the shaving means at the top surface of the glass substrate.However, with a deposited film 1 a 1 mm or more thick, variations in itsthickness and other factors may cause the tip of the shaving means to bepositioned above the glass substrate surface, leading to insufficientshaving of the deposited film, with the deposited film left at thebottom of the shaved groove, or may cause the tip of the shaving meansto be positioned below the glass substrate surface, leading tointerference of the tip of the shaving means with the edge of the glasssubstrate and, in the worst case, even to the destruction of thescribing unit. This problem is likely to arise especially at the edge ofthe glass substrate, i.e., when the deposited film 1 a starts beingshaved. The eleventh embodiment is devised to overcome this problem.Specifically, a clearance portion (non-film-deposited portion) is formedalong the edges of a large-format glass substrate to be shaved, and,when the glass substrate is cut apart, the non-film-deposited portion isdiscarded. In the method shown in FIG. 19(a), a clearance portion S,where no deposited film is formed, is formed along the edges of alarge-format glass substrate, i.e., the raw material. The dimension Svaries according to the thickness of the deposited film and the controlability of the cutting apparatus, and is set equal to, for example, 2 to10 mm. In this method, first, the tip of the shaving means is broughtinto contact with the glass surface within the portion S having thedimension S, and then the scribing unit is moved. Variations in thecontrol of the tip of the shaving cutter are absorbed within thedimension S so that the tip is securely brought into contact with theglass substrate surface, and the deposited film can be shaved with amargin secured from the edge of the deposited film. In the method shownin FIG. 19(b), instead of removing the deposited film in a clearanceportion S beforehand, the fact that the deposited film is shaved withthe tip of the shaving means loaded with a downward pressing force ofabout 1 to 40 N is exploited. The tip of the shaving means startsshaving the deposited film from a point near the edge of thefilm-deposited glass at the left of the figure, and then reaches theglass substrate surface within the portion S′ while describing a curveR5 as shown in the figure. Part of the deposited film is left in thehatched portion in the figure, and therefore the portion S′ is discardedwhen the glass substrate is cut apart. If FIG. 19(b) is assumed to showscribing in the Y direction, then it shows how, after shaving andscribing have been performed in the X direction to form the shavedgroove 5, shaving and scribing are performed in similar manners in adirection 90° apart therefrom to form a grid-like pattern. In thisembodiment, when the glass substrate is scribed into a grid-likepattern, it is necessary to form the clearance portion S or S′ allaround the edges in both of the methods (a) and (b). S1 and S2 representthe pitch at which scribing is performed to form strip-shaped sections,and are usually set equal to each other.

The eleventh embodiment applies to both a cutting method and a cuttingapparatus as described above. In a method for scribing a film-depositedglass, even in an extreme case in which the deposited film is shavedmanually, there arises the problem of the deposited film being leftunshaved at the edges of a large-format glass substrate before scribingand cutting. This problem is overcome by forming a non-film-depositedportion along the edges as described in the eleventh embodiment. On theother hand, in the cutting apparatus of the ninth embodiment, the tip ofthe shaving means is positioned at the glass surface of the glasssubstrate at the start of shaving by detecting the position of thesurface of the deposited film by the use of a detecting means, thencorrecting the thickness of the deposited film, and then setting thevertical position of the tip of the shaving means at the start ofshaving. This, however, is difficult to realize with satisfactoryaccuracy when there are large variations in the thickness of thedeposited film. This problem also is solved by forming anon-film-deposited portion along the edges of the glass substrate as inthe eleventh embodiment. This greatly alleviates the burden on thedesign and construction of the cutting apparatus.

FIG. 20 is a diagram illustrating the principles of the cuttingapparatus of a twelfth embodiment of the invention. In this embodiment,the cutting method of the seventh embodiment described earlier withreference to FIG. 9 is applied to a cutting apparatus. In the cuttingapparatus of this embodiment, as shown in FIG. 20(a), in the workpiecestage 3, there are formed a plurality of negative pressure supplyingpaths 209 in an appropriate arrangement to permit the glass substrate 1to be secured by an unillustrated negative pressure supplying means suchas vacuum, and there are also formed elongate openings 3 a at intervalscorresponding to the pitch of scribing to permit the scribing means 4 toscribe the glass substrate 1 from below the bottom surface thereof. Inthe cutting apparatus of this embodiment, the tip of the shaving meansfor shaving the deposited film 1 a formed on the glass substrate 1 andthe tip of the scribing means 4 are located on a vertical line as seenfrom the direction of their movement, and move together. Thus, a scribedline 5 c is formed right below the shaved groove 5 formed by the shavingmeans. In this embodiment, cutting needs to be performed, in the glasssubstrate cutting step after scribing, along the shaved groove 5 formedin the deposited film. Thus, as shown in FIG. 20(a), the cutter wheel 4a at the tip of the scribing means 4 needs to be located, as describedabove, vertically right below the shaved groove 5 as seen from thedirection of its movement, but not so accurately in thefrontward/backward direction, i.e., in the direction of the movement ofthe cutter. The glass substrate needs to be scribed with a load of about10 N applied thereto, depending on the thickness of the glass. Thus, ina cutting apparatus in which the glass substrate is scribed from below,the upward pressing force exerted by the scribing means 4 may cause theglass substrate 1 to come off the chucking means provided on theworkpiece stage 3. To prevent this, a balance wheel 205 shown in FIG.20(a) for balancing with the load is disposed immediately at the rear ofthe shaving means in the direction of its movement. The balance wheel205 has, at its tip, a freely rolling wheel having substantially thesame dimensions and shape as the cutter wheel 4 a at the tip of thescribing means 4 and formed of a soft material such as polyurethanerubber. To stably secure the glass substrate 1 on the workpiece stage 3,the balance wheel 205 is located immediately at the rear of the shavingmeans so as to move as if following the shaving means while applying apressing force P2 that balances with the scribing load P1. Using aweight-shaped load applying means to apply a load directly to thefilm-deposited surface to reinforce the force with which the glasssubstrate is secured may destroy or scratch the protective film. Bycontrast, in this embodiment, at the same time that the glass substrateis scribed from below the bottom surface thereof, the load balancewheel, loaded with the desired pressing force, is made to roll along thebottom of the shaved groove formed on the top surface of the glasssubstrate by the shaving means shaving the film-deposited surface. Thismakes it possible to perform scribing with the glass substrate stablysecured, without the risk of touching and thereby scratching orotherwise damaging the deposited film 1 a. In FIG. 20(a), the shavingmeans is omitted.

After scribing, the glass is cut apart (separated) by applying a loadfrom below the surface opposite to the scribed surface so as to developthe crack in the scribed line. Accordingly, in the ninth to eleventhembodiments, a scribed line is formed along the bottom of the shavedgroove 5, and a load is applied from below the surface opposite to thefilm-deposited surface to achieve cutting. By contrast, in the twelfthembodiment, at the same time that scribing is performed on the bottomsurface of the glass substrate, the deposited film right above thescribed line is shaved to form a shaved groove having a cross sectionwith the desired dimensions and shape. Then, as shown in FIG. 20(b), awire 207 formed of resin, such as urethane, or metal and havingappropriate dimensions is laid in the shaved groove 5 right above thescribed line 5 c, and a roller 206 having, at its tip, a groove thatmoderately engages with the wire is placed on the wire so as to rollalong it while applying, through the wire, a load P3 of 50 to 200 N. Inthis way, it is possible to realize a cutting apparatus that permits theshaving of a deposited film from a glass substrate and the scribing andcutting of the glass substrate without reversing the glass substrate.Reference numeral 208 represents a cushion material used at the time ofcutting. In this embodiment, the cleaving of glass after scribing may beintegrated into a cutting apparatus provided additionally with acleaving function which is capable of both scribing and cleaving, orglass may be first scribed on a cutting apparatus and then cleaved on acleaving machine. In this embodiment, in any of the steps from thescribing to cutting of the glass substrate, including the securingthereof on the apparatus, there is no need at all to touch or press thefilm-deposited surface. This makes it possible to maintain and protectthe quality of the deposited film. Instead of the roller 206, aplate-shaped pressing member that positionally fits the bottom of theshaved groove 5 may be used to achieve cutting.

FIGS. 21 and 22 show a thirteenth embodiment of the invention. Thisembodiment is characterized in that, in principle, the step of shavingthe deposited film and the step of scribing are performed as separatesteps, and that, in the step of scribing, which is the downstream step,waste portions 11 c are formed on the film-deposited surface so that theglass substrate is supported, at the waste portions 11 c formed on thefilm-deposited surface thereof, on projections 13 a formed on theworkpiece stage shown in FIG. 22.

FIG. 21 illustrates how the deposited film 11 a is shaved in such a wayas to separate product portions, which are to be used as products suchas liquid crystal display devices, and waste portions. FIG. 22 shows howscribing is performed on the opposite surface of the glass substrate,right below (in the positional relationship shown in FIG. 22, rightabove) the shaved groove, after the deposited film 11 a is shaved inFIG. 21.

Now, the workings and other features of this embodiment will bedescribed with reference to what is shown in the figures. The glasssubstrate 11, like the ones used in the embodiments described above, hasa deposited film 11 a formed on one surface thereof. In the workpiecestage 3, there are formed a plurality of suction paths 6 at apredetermined pitch to permit the glass substrate 11 to be secured by anegative pressure supplying means such as vacuum. From and relative toone edge, indicated as A, of the glass substrate 11, shaved grooves 15are formed by an unillustrated shaving cutter at pitches correspondingto the width-direction dimensions of the waste portions 11 c and theproduct portions 1 d. How the shaved grooves 15 are formed is the sameas in the first and second embodiments, and therefore detailedexplanations will not be repeated. The dimensions of the waste portions11 c are determined according to the thicknesses of the glass substrateand the deposited film 11 a and the conditions related to mechanicalstrength such as the dimensions of the product portions 11 d and thedimensions of the suction paths 16 shown in FIG. 22. The waste portions11, which will eventually be discarded, should be made as small aspossible. However, in the step of breaking (cutting) the glasssubstrate, in a case where it is cut apart by applying a load to thesurface opposite to the scribed surface, if the waste portions are madetoo small as compared with the thickness of the glass substrate 11, itmay be difficult to perform cutting. This needs to be taken intoconsideration when the dimensions of the waste portions are determined,while seeing to it that they are larger than the minimum requireddimensions of the workpiece stage projections 13 a shown in FIG. 22 anddescribed later. The dimensions of the product portions 1 d aredetermined according to the size of the products, such as liquid crystaldisplay devices, with finishing margins added thereto.

FIG. 22 illustrates how, after the shaving step shown in FIG. 21, theglass substrate 11 is turned upside down and secured on the workpiecestage 13 so that the surface opposite to the shaved surface is scribed.In this embodiment, the workpiece stage 13 used to perform scribing isdifferent from the workpiece stage 3 shown in FIG. 21, and hasprojections 13 a and recesses 13 b arranged, as shown in the figure,alternately in positions corresponding to the dimensions and pitch ofthe waste portions formed in the shaving step. The top surfaces of theprojections 13 a are level, and securely support thefilm-deposited-surface side of the waste portions 11 c shown in FIG. 21from which the deposited film 11 a has been shaved and removed. Here,secure supporting is achieved through the suction paths 16 by the samenegative pressure supplying means as used conventionally. In this state,scribed lines are formed by a scribing cutter 4 right above, as seen inthe positional relationship shown in FIG. 22, the shaved grooves 15formed on the glass substrate 11. Scribing right above the shavedgrooves 15 is achieved as follows. Relative to the edge A, by the use ofa combination of a well-known detecting means, such as an opticalsensor, or a positioning jig, a means for driving the scribing cutter 4,such as a ball screw or a timing belt driven by a servo motor, and acontrolling means, such as a numerical controller, scribed lines caneasily be formed at desired places on the opposite surface of the glasssubstrate corresponding to the places where the shaved grooves 11 ashown in FIG. 21 are formed. The recesses 13 b help prevent thefilm-deposited portions of the product portions 1 d from touching theworkpiece stage and thereby being scratched or destroyed.

In this embodiment, scribing is performed on the surface of the glasssubstrate opposite to the film-deposited surface. This makes it possibleto perform scribing without being affected by the deposited film in thescribing step. Moreover, the deposited film on the surface opposite tothe scribed surface is shaved to form grooves at places corresponding tothe scribed lines. Thus, even the step of breaking the glass substrateis not affected by the presence of the deposited film layer. Thisembodiment is described above as a method in which first the step ofshaving the deposited film is performed and then scribing is performed.However, since, as described above, it is easy to control where to formthe shaved grooves 15 a and the scribed lines 15 a by the use of thecontrolling means mentioned above, it is also possible to perform thescribing step shown in FIG. 22 first.

Next, a fourteenth embodiment of the invention will be described withreference to FIG. 23. The third embodiment described above deals withthe shaving of a deposited film and scribing performed on a glasssubstrate having a deposited film formed on one surface thereof. Thisembodiments deals with a cutting method for a glass substrate havingdeposited films formed on both surfaces thereof. This embodiment is thesame as the third embodiment in that a glass substrate 21 is dividedinto waste portions 21 c and product portions 21 d. A workpiece stage 23having projections 23 a and recesses 23 b formed at places dimensionallycorresponding to those portions is used in both of the shaving andscribing steps. The shaving of the deposited films is performed, by theuse of the workpiece stage 23 having the projections 23 a and therecesses 23 b formed as shown in FIG. 23, by first shaving the depositedfilm on one surface of the glass substrate having the deposited filmsformed on both surfaces thereof, and then turning the glass substrate 21upside down and shaving the deposited film on the opposite surface.Vertical alignment of the places at which to form shaved grooves and theplaces at which to form scribed lines on both surfaces is achievedeasily relative to the edge A by the use of the controlling meansmentioned above. In this embodiment, it is possible to shave thedeposited film on one surface and then on the opposite surface and thenperform scribing on one surface and then on the opposite surface;alternatively, it is also possible to shave the deposited film and thenperform scribing on one surface and then perform those two steps on theopposite surface.

As described above, in the embodiments described hereinbefore,strip-shaped portions of a deposited film as wide as necessary to formcracks are removed, and then cracks for cutting are formed along theexposed strip-shaped regions on a glass substrate. In this way, it ispossible to realize a cutting method and a cutting apparatus that permitthe cutting of a glass substrate having any type of deposited filmformed thereon, from a thin film such as an overcoating film ortransparent electrode to a film such as a polarizer plate or a depositedfilm up to 1 to 2 mm thick such as a resin film or protective film,without being affected by the presence of the deposited film. It is tobe understood that the present invention may be carried out in any othermanner than specifically described above as embodiments, and thatvarious variations and modifications are possible within the scope ofthe invention.

In the following part of the specification, liquid crystal panels andapparatuses for fabricating them according to the invention will bedescribed with reference to the drawings. First, the liquid crystalpanel of a fifteenth embodiment of the invention will be described indetail. FIG. 24 is a perspective view showing the appearance of theliquid crystal panel of the fifteenth embodiment, with the obverse sideshown at (a) and the reverse side shown at (b), and FIG. 25 is avertical sectional view of the liquid crystal panel.

This liquid crystal panel 350 is composed of a pair of substrate cells351 a and 351 b bonded together with liquid crystal sealed in between(here, the substrate cell 351 a is a TFT substrate and will hereinafterbe referred to as the “TFT substrate cell” also; the substrate cell 351b is a color filter substrate and will hereinafter be referred to as the“color filter substrate cell” also). One end of the TFT substrate cell351 a protrudes from one end of the color filter substrate cell 351 b toform a protruding portion 351 aa, and connection terminals 353 by way ofwhich the liquid crystal panel is driven are formed on the inner surfaceof the protruding portion 351 aa. To these connection terminals 353 isconnected an FPC (flexible printed circuit) or COG (chip on glass) that,when the liquid crystal panel 350 is incorporated in a liquid crystaldisplay device, receives electric signals and achieves display on theliquid crystal panel 350.

The liquid crystal panel 350 is designed for use in a backlit liquidcrystal display device, and thus has polarizer plates 352 a and 352 bbonded to the outer surfaces of the substrate cells 351 a and 351 b,respectively, almost all over the entire areas thereof (here, thepolarizer plate 352 a is located on the side of the TFT substrate cell351 a and will hereinafter be referred to as the “TFT-side polarizerplate cell” also; the polarizer plate 352 b is located on the side ofthe color filter substrate cell 351 b and will hereinafter be referredto as the color-filter-side polarizer plate cell” also). From theviewpoint of the functions required of the polarizer plates 352 a and352 b, they simply have to cover the display area (not shown); that is,they have only to be made substantially equally large and arranged so asto face each other with the substrate cells 351 a and 351 b sandwichedin between. In the liquid crystal panel 350 of this embodiment, however,the TFT-side polarizer plate cell 352 a is extended so as to cover theouter surface of the protruding portion 351 aa. The reason is asfollows.

The substrate cells 351 a and 351 b constituting the liquid crystalpanel 350 are each very thin, for example about 0.4 to 0.7 mm whenformed of glass. Thus, while they have increased mechanical strengthwhere they are bonded together to have twice the thickness, i.e., overand around the display area, the protruding portion 351 aa, where theTFT substrate cell 351 a alone appears and is as thick as it is, has lowmechanical strength. On the other hand, the TFT-side polarizer platecell 352 a is about 0.2 to 0.6 mm thick, and this thickness is exploitedto reinforce the protruding portion 351 aa. This is the reason that theTFT-side polarizer plate cell 352 a is extended so as to cover the outersurface of the protruding portion 351 aa. This increases the mechanicalstrength of the protruding portion 351 aa. As a result, when the liquidcrystal panel is transported from one place to another or assembled intoa liquid crystal display device, even if it is hit or dropped, theprotruding portion 351 aa is less likely to be cracked or deformed, orbroken at a corner.

The mechanical strength of the protruding portion 351 aa can besatisfactorily increased by leaving 1 mm or less as a distance h (seeFIG. 25) between the edge of the TFT-side polarizer plate cell 352 a andthe edge of the protruding portion 351 aa, i.e., the width over whichglass is exposed outward. Similar widths are secured between the otheredges of the polarizer plates 352 a and 352 b and the edges of thesubstrate cells 351 a and 351 b.

Moreover, the edges 352 aa and 352 ba of the polarizer plates 352 a and352 b are all so formed as to have a vertical section that becomesthinner and thinner toward the substrate cells 351 a and 351 b.Specifically, these edges 352 aa and 352 ba are formed so as to haveinclined or curved surfaces by a laser radiating mechanism 420 orcutting mechanism 460 provided in the liquid crystal panel fabricatingapparatus that will be described in detail later. This prevents, whenthe liquid crystal panel 350 is transported from one place another orassembled into a liquid crystal display device, the edges 352 aa and 352ba (especially at corners) of the polarizer plates 352 a and 352 b frombeing caught accidentally, and thereby prevents exfoliation. In a casewhere protective films are formed on the outer surfaces of the polarizerplates 352 a and 352 b so as to be integral therewith, the abovestructure prevents exfoliation of those films from the polarizer plates352 a and 352 b.

Now, the preferred configuration of the edges 352 aa and 352 ba will bedescribed. To evaluate various configurations of the edges 352 aa and352 ba, by using, as a representative, the liquid crystal panelfabricating apparatus 400 of the eighteenth embodiment described indetail later, experiments were conducted to see how varying the shape ofthe cutting edge of the blade 461 of its cutting mechanism 460 (as byinterchanging blades having C-shaped and trapezoidal cross sections asshown in FIGS. 32(a) and 32(b)) affects the substrate cells 351 a and351 b. The results are shown in FIG. 26. FIG. 26 is a diagramschematically showing the relationship between the inclination angle gof the edges of the polarizer plates 352 a and 352 b shown in FIG. 25(i.e., the rising angle of the side cutting edges of the blade 461) andthe resulting properties, i.e., how the angle g affects the polarizerplates 352 a and 352 b and the substrate cells 351 a and 351 b. Forangles from 90° to over 135°, the following four items were evaluated:the mechanical strength of the protruding portion 351 aa, delta-shapedchipping in the polarizer plates 352 a and 352 b, exfoliation ofprotective films, and residues of the adhesive bonding together thesubstrate cells 351 a and 351 b and the polarizer plates 352 a and 352b. For different ranges of inclination angles g, the result of theevaluation of each item was classified into one of three grades,specifically good, fair, and poor. As shown in FIG. 26, when theinclination angle g is in the range of from over 90° to 135°, good orfair properties are obtained in all of the items. Thus, the preferredconfiguration of the edges 352 aa and 352 ba is forming them as surfacesinclined at an angle in that range.

It is to be noted that the preferred condition found out in the aboveexperiments applies in cases where the edges 352 aa and 352 ba areformed so as to have inclined surfaces. Needless to say, the edges 352aa and 352 ba may be formed to have curved surfaces instead so long asthey have a vertical section that becomes thinner and thinner toward thesubstrate cells 351 a and 351 b. The substrate cells 352 aa and 352 bamay be formed of any other material than glass. Where fabricationefficiency is not given the highest priority, the bonding of thepolarizer plates 352 a and 352 b may be achieved by first cutting apartindividual substrate cells 351 a and 351 b and then bonding theretopolarizer plates already cut into predetermined sizes.

Now, liquid crystal panel fabricating apparatuses according to theinvention which are suitable to fabricate the liquid crystal panel 350described above will be described with reference to the drawings. Howthe liquid crystal panel 350 is fabricated will be describedspecifically last.

First, the liquid crystal panel fabricating apparatus of a sixteenthembodiment of the invention will be described. FIG. 27 is a perspectiveview schematically showing the appearance of the liquid crystal panelfabricating apparatus of the sixteenth embodiment, and FIG. 28 is anenlarged view of a principal portion of the glass substrate. As shown inFIG. 27, the liquid crystal panel fabricating apparatus 400 is composedessentially of a bed (not shown) serving as a workpiece stage, on whicha strip-shaped glass substrate 301 having a polarizer plate 302 bondedon the top surface thereof is placed, and a movable unit 410horizontally movable over the bed. The movable unit 410 has a laserradiating mechanism 420, a wheel cutter 430 for scribing, and a distancesensor 440 fitted thereto so as to protrude downward. These movetogether with the movable unit 410.

The laser radiating mechanism 420 is a CO2 laser device as used in acommon laser cutting/shaping machine, and emits a high power laser beam.The wheel cutter 430, as will be described later, forms cracks in theglass substrate 301 to permit it to be cut apart. The wheel cutter 430has a diameter u1 of about 2.5 mm, and has an obtuse cutting edge anglew1 of about 120 to 150° (see FIG. 29). The wheel cutter 430 is supportedthrough a spring or air spring on the movable unit 410 so as to apply apredetermined pressing force to the glass substrate 301. The distancesensor 440 is a touch sensor for detecting the displacement of the topsurface of the polarizer plate 302 on the glass substrate 301 placed onthe bed, and is used to keep constant the distances from the laserradiating mechanism 420 and the wheel cutter 430 to the top surface ofthe polarizer plate 302. This control is performed to stabilize thefocus of the laser beam emitted by the laser radiating mechanism 420 andto stabilize the pressing force exerted by the wheel cutter 430.Incorporating these, the movable unit 410 is moved at a speed of about200 to 500 mm/sec, which is the appropriate speed at which to move thewheel cutter 430. Needless to say, the laser radiating mechanism 420 issupposed to yield a laser output sufficient to cope with that speed.

Next, the operation of the liquid crystal panel fabricating apparatus400 described above will be described. As shown in FIG. 27, the movableunit 410 moves in the direction indicated by an arrow D along theboundary between cells on the glass substrate 301. Here, the laserradiating mechanism 420, radiating a laser beam toward the polarizerplate 302, moves ahead of the wheel cutter 430. Thus, the portion of thepolarizer plate 302 irradiated with the laser beam is melted and removedby heat, exposing the glass substrate 301 there so as to form astrip-shaped region 311. Following the laser radiating mechanism 420,the wheel cutter 430 moves along the strip-shaped region 311 and formsthere a crack 312 for cutting (hereinafter referred to as a “scribedline” also) (see FIG. 28).

In this way, the crack 312 is formed along the boundary between cells onthe glass substrate 301. Thereafter, when a load is applied to the glasssubstrate 301 as required, the glass substrate 301 readily breaks apartalong the crack 312, producing liquid crystal panels. Even without aload applied to the glass substrate 301, when the crack 312 is formed,it may immediately develop to cause the glass substrate 301 to breakapart. In this case also, the glass substrate 301 is cut apart along thecrack 312. In practice, for higher fabrication efficiency, the movableunit 410 is moved horizontally along all of a plurality of boundariesbetween cells to repeat the above-described operation of the liquidcrystal panel fabricating apparatus 400, then the glass substrate 301 isturned upside down, then scribing is performed also on the reverse sideof the glass substrate 301 by the use of the wheel cutter 430, and thenthe glass substrate 301 is cut apart. In a case where a polarizer plate302 is bonded also to the reverse side, the above-described operation ofthe liquid crystal panel fabricating apparatus 400 is performed also onthis side.

As described above, the liquid crystal panel fabricating apparatus 400is highly effective in efficiently producing high-quality liquid crystalpanels because it prevents a glass substrate 301 from breaking atinappropriate places and prevents a polarizer plate 302 from exfoliatingaccidentally even when dealing with a glass substrate 301 having apolarizer plate 302 bonded thereto.

The laser radiating mechanism 420 may be of any other type than a CO2laser device. The wheel cutter 430 may have any other shape anddimensions. The distance sensor 440 may be of any other type than atouch sensor.

Next, the liquid crystal panel fabricating apparatus of a seventeenthembodiment of the invention will be described with reference to FIG. 30.In this figure, such portions as have the same names and serve the samepurposes as in FIGS. 27 to 29 are identified with the same referencenumerals, and overlapping explanations will be omitted. This appliesalso to the eighteenth to twenty-first embodiments described later. Theseventeenth embodiment differs from the sixteenth embodiment in that thewheel cutter 430 is replaced with a gas spraying mechanism 450. As shownin FIG. 30, the movable unit 410 has, in the stage following the laserradiating mechanism 420, a gas spraying mechanism 450 having a nozzle451 through which a gas is sprayed to the strip-shaped region 311 on theglass substrate 301. The gas sprayed through the nozzle 451 is, forexample, compressed air or an inert gas (such as nitrogen).

This liquid crystal panel fabricating apparatus 400 operates basicallyin the same manner as that of the sixteenth embodiment described above,but operates differently therefrom when forming scribed lines. Thedifference is as follows. The laser beam radiated from the laserradiating mechanism 420 not only heats and melts and thereby removes aportion of the polarizer plate 302, but simultaneously heats thestrip-shaped region 311 exposed on the glass substrate 301 as a result,making the strip-shaped region 311 hot. The hot strip-shaped region 311is then rapidly cooled by the gas sprayed from the nozzle 451 of the gasspraying mechanism 450, which follows the laser radiating mechanism 420.This causes the strip-shaped region 311 to contract and produce a crack.In this embodiment, this crack is used as the crack 312.

Next, the liquid crystal panel fabricating apparatus of an eighteenthembodiment of the invention will be described with reference to FIGS. 31and 32. The eighteenth embodiment differs from the sixteenth embodimentin that the laser radiating mechanism 420 is replaced with a cuttingmechanism 460. As shown in FIG. 31, the movable unit 410 has, in thestage preceding the wheel cutter 430, a cutting mechanism 460 composedof a blade 461 that protrudes at a predetermined angle relative to thepolarizer plate 302.

This liquid crystal panel fabricating apparatus 400 operates basicallyin the same manner as that of the sixteenth embodiment described above,but operates differently therefrom when removing portions of thepolarizer plate 302. The difference is as follows. As the cuttingmechanism 460 moves along the boundary between cells on the glasssubstrate 301, a portion of the polarizer plate 302 is shaved off by theblade 461 as if by a wood chisel, and a strip-shaped region 311 isexposed on the glass substrate 301. The waste strip 302 a of thepolarizer plate 302 shaved off is ejected along the blade 461.

With this liquid crystal panel fabricating apparatus 400, it is easy toform strip-shaped regions 311. In addition, the cutting mechanism 460requires only a mechanical structure. This makes the control of thecutting depth and maintenance easy.

Now, examples of the shape of the cutting edge of the blade 461 will bedescribed with reference to FIG. 32. With a blade having a C-shapedcross section as shown in FIG. 32(a), it is possible to shave thepolarizer plate 302 with a constant width. This helps stabilize thewidth of the strip-shaped regions 311 exposed on the glass substrate301. With a blade having a trapezoidal cross section as shown in FIG.32(b), in addition to the same advantages as obtained with the bladehaving a C-shaped cross section described above, the cut surfaces of thepolarizer plate 302 left on the glass substrate 301 are inclined. Thismakes the polarizer plate 302 less likely to exfoliate accidentally.Moreover, the friction drag exerted by the blade 461 on the waste strip302 a of the polarizer plate 302 shaved off is reduced. This permitssmooth ejection of the waste strip 302 a along the blade 461.

With a blade having a semicircular cross section as shown in FIG. 32(c),in addition to the same advantages as obtained with the blades describedabove, the friction drag exerted by the blade 461 on the waste strip 302a shaved off is further reduced, and the blade 461 itself can beproduced easily. It should be noted, however, that the strip-shapedregions 311 are exposed with a smaller width. With a blade having acircular cross section as shown in FIG. 32(d), in addition to the sameadvantages as obtained with the blade having a semicircular crosssection described above, it is possible, by additionally providing arotation mechanism for rotating the cutting edge, to use the wholecircumference of the cutting edge for cutting. This helps prolong theworking life of the blade 461. In this case, however, it is alsonecessary to additionally provide a mechanism for ejecting the wastestrip 302 a.

Next, the liquid crystal panel fabricating apparatus of a nineteenthembodiment of the invention will be described with reference to FIGS. 33to 36. The nineteenth embodiment differs from the eighteenth embodimentin that the cutting mechanism 460 has a modified construction. As shownin FIG. 33, the movable unit 410 has the cutting mechanism 460 in thestage preceding the wheel cutter 430, and, as shown in FIGS. 34 and 35,the cutting mechanism 460 has a pair of blades 462 and 463 arranged at apredetermined interval v so as to face each other and each having acutting edge and a blade 464 arranged between those blades 462 and 463at their bottom. The blade 464 has a width equal to the predeterminedinterval v, and thus serves to keep the blades 462 and 463 constantly atthe interval v. Between the blades 462 and 463 at their top, a supportmember 465 is arranged that has, like the blade 464, a width equal tothe predetermined interval v. The support member 465 is supported by themovable unit 410. These blades 462, 463, and 464 and the support member465 are built into a single unit with screws or rivets for easyreplacement.

The liquid crystal panel fabricating apparatus 400 structured asdescribed above operates basically in the same manner as that of theeighteenth embodiment described above, but operates differentlytherefrom when removing portions of the polarizer plate 302. Thedifference is as follows. As shown in FIGS. 33 and 36, as the cuttingmechanism 460 moves along a boundary between cells on the glasssubstrate 301 in the direction of the shorter sides thereof, first, theblades 462 and 463 cut apart a strip-shaped portion of the polarizerplate 302. Next, the strip-shaped portion of the polarizer plate 302,thus cut apart, is shaved off the glass substrate 301 by the blade 464,and is removed, as a waste strip 302 a, along the blade 464.Simultaneously, a strip-shaped region on the glass substrate 301 isexposed.

With this cutting mechanism 460, the same advantages as achieved by theeighteenth embodiment described above are achieved. In addition, sincethe cutting mechanism 460 is composed of a plurality of blades, forexample, the width of the strip-shaped region 311 on the glass substrate301 can be changed simply by interchanging the blade 464. Moreover, whenone or two of the blades have worn out, only those can be replacedindividually. That is, varying widths of the strip-shaped region 311 caneasily be coped with, and the running costs of the blades themselves areeffectively reduced.

Next, the liquid crystal panel fabricating apparatus of a twentiethembodiment of the invention will be described with reference to FIG. 37.The twentieth embodiment differs from the nineteenth embodiment in thatthe pair of blades 462 and 463 are given modified shapes so as to reducethe cutting resistance to the polarizer plate 302. When the blades 462and 463 each have a single cutting edge as in the nineteenth embodiment,cutting a thick polarizer plate 302 with them inevitably results in ahigh cutting load imposed on their cutting edges. In other words, thecutting resistance to the polarizer plate 302 is high, and this invitesthe polarizer plate 302 to be deformed while being cut or causesdelta-shaped chipping at the end of cutting. To overcome these problems,in this embodiment, as shown in FIG. 37, the blades 462′ and 463′ areeach provided with a plurality of (in the figure, two) cutting edgeshaving smaller and smaller cutting depths in the direction of cutting(in the figure, the direction indicated by an arrow D). This reduces thecutting load imposed on each cutting edge, and thus reduces the cuttingresistance to the polarizer plate 302, making the above-describedproblems less likely.

Next, the liquid crystal panel fabricating apparatus of a twenty-firstembodiment of the invention will be described with reference to FIGS. 38and 39. The twenty-first embodiment differs from the nineteenthembodiment in that the pair of blades 462 and 463 are replaced withwheel cutters. As shown in FIG. 38, the movable unit 410 has, in thestage preceding to the wheel cutter 430, a cutting mechanism 460, and,as shown in FIG. 39, this cutting mechanism 460 has a pair of wheelcutters 466 and 467 arranged coaxially at a predetermined interval v soas to face each other, instead of the pair of blades 462 and 463 shownin FIGS. 34 and 35. With this structure, it is possible to furtherreduce the cutting resistance to the polarizer plate 302. Here, thewheel cutters 466 and 467 are given an acute cutting edge angle w2 inthe range of from 30 to 90° to secure a sufficient cutting depth whilepreventing the polarizer plate 302 left on the glass substrate 301 fromexfoliating accidentally at a cut edge thereof. The wheel cutters 466and 467 are given a diameter u2 in the range of from 5 to 10 mm tosecure sufficient space for their rotation shaft, to secure sufficientperipheral speed for fast cutting, and secure sufficient mechanicalstrength in the wheel cutters 466 and 467 themselves.

Now, supplementary descriptions common to the eighteenth to twenty-firstembodiments will be given. In a liquid crystal panel fabricatingapparatus 400 according to the invention, strip-shaped portions of thepolarizer plate 302 are shaved off and removed by a blade or wheelcutter. Meanwhile, if the blade or the like reaches the glass substrate301, the cutting edge of the blade or the like may chip, or the surfaceof the glass substrate 301 may be scratched. Such a scratch, inparticular, is undesirable because it causes the glass substrate 301 tobreak at an unexpected place and causes degradation in its quality. Onthe other hand, in reality, between the glass substrate 301 and thepolarizer plate 302, there exits a very thin adhesive layer that bondsthem together. Therefore, the cutting edge of the blade or the like isinitially so set as to be located within the adhesive layer so as not toreach the glass substrate 301, and in addition, in the middle ofcutting, it is monitored and controlled by a position sensor 440.Alternatively, it is also possible to use as the material of the blade amaterial that is harder than the polarizer plate 302 but softer than theglass substrate 301.

The strip-shaped regions 311 on the glass substrate 301 are given awidth in the range of from 1 to 3 mm, preferably in the range of from 1to 2.5 mm. This helps secure a sufficient effective area on thepolarizer plate 302 in each individual liquid crystal panel, and permitscracks 312 for cutting apart to be formed easily without degradation inquality. Thus, the dimensions of the blade or the like need to be setaccordingly. This can be achieved easily, in the nineteenth totwenty-first embodiments in particular, by setting the interval vbetween the pair of blades 462 and 463 or wheel cutters 466 and 467 inthe range stated above.

Moreover, to permit the waste strips 302 a of the polarizer plate 302shaved off to be ejected smoothly without accumulating on the blade orthe like, the blade or the like is coated with Teflon (R) or diamond toprevent the wastes 2 a from adhering thereto. This prolongs the workinglife of the blade or the like.

A liquid crystal panel fabricating apparatus according to the inventionmay be structured in any other manner than specifically described aboveas embodiments, and many variations and modifications are possiblewithin the scope of what is claimed as the invention. For example, theglass substrate 301 and the polarizer plate 302 are bonded together withany type of adhesive, examples including common acrylic- orsilicone-based adhesives. In the nineteenth to twenty-first embodimentsin particular, the polarizer plate 302 is shaved off by the blade 465,and therefore it is advisable to select a type of adhesive that caneasily be shaved off while offering sufficiently strong adhesion toproduce acceptable products. It is advisable to bond a protectivelaminate film on the surface of the polarizer plate 302, because then,by removing the protective laminate film when products are shipped, itis possible to remove molten particles and cullet (fine glass particlesused when glass is cut) deposited on the surface. In the embodimentsdescribed above, the movable unit 410 moves relative to the bed;alternatively, the bed may be made movable together with the glasssubstrate 301 placed thereon.

Next, how the liquid crystal panel 350 described earlier is fabricatedby the use of a liquid crystal panel fabrication apparatus 400 asdescribed above will be described in detail with reference to thedrawings. FIG. 40 is a perspective view showing the appearance of aglass substrate of which the liquid crystal panel 350 is formed, FIG. 41is a side view schematically showing the liquid crystal panelfabricating apparatus with respect to the glass substrate, and FIG. 42is a vertical sectional view of the glass substrate after the operationof the liquid crystal panel fabricating apparatus. FIG. 43 is aperspective view showing the appearance of the glass substrate, with theTFT-side surface thereof shown at (a) and the cutting positions on thecolor-filter-side surface thereof shown at (b). Here, asrepresentatives, the liquid crystal panel fabricating apparatus 400 ofthe eighteenth embodiment (see FIG. 31) is used, and, as the blade 461of its cutting mechanism 460, a blade having a cutting edge with atrapezoidal cross section (see FIG. 32(b)) is used.

First, as the material of which the liquid crystal panel 350 is formed,a glass substrate 301 is prepared that is composed of a pair of a TFTsubstrate 301 a and a color filter substrate 301 b bonded together. Thisglass substrate 301 has a plurality of TFT substrate cells 51 a and aplurality of color filter substrate cells 51 b arranged adjacent to oneanother in a grid-like pattern. Between each pair of a TFT substratecell 51 a and a color filter substrate cell 51 b is sealed liquidcrystal. Moreover, to the outer surfaces of the TFT substrate 301 a andthe color filter substrate 301 b, a TFT-side polarizer plate 302 a and acolor-filter-side polarizer plate 302 b are respectively bonded so as tocover all the TFT substrate cells 51 a (FIG. 40). The TFT-side polarizerplate 302 a and the color-filter-side polarizer plate 302 b haveprotective films laid on the outer surfaces thereof. Next, the glasssubstrate 301 is placed on the bed of the liquid crystal panelfabricating apparatus 400, with the TFT substrate 301 a up. Then, themovable unit 410 is moved in one direction (in the direction indicatedby the arrow D in FIGS. 31 and 18) from one edge of the glass substrate301 to another along one U1 of the mutually parallel boundaries U1, U2,. . . (see FIG. 43) between adjacent TFT substrate cells 351 a. As aresult, a portion of the TFT-side polarizer plate 302 a is shaved off bythe blade 461, and a strip-shaped region 311 a (see FIG. 42) is exposedon the TFT substrate 301 a. Subsequently, the wheel cutter 430 is movedalong the strip-shaped region 311 a to form a scribed line 312 a (seeFIG. 42).

Thereafter, the glass substrate 301 is moved translationally within ahorizontal plane so that the above operation is repeated along theboundaries U2, U3, . . . successively. Next, the glass substrate 301 isrotated through 90° within a horizontal plane so that the aboveoperation is repeated along the boundaries Q1, Q2, . . . (see FIG. 43)perpendicular to the boundaries U1, U2, . . . to form scribed lines 312b (see FIG. 43).

Next, the glass substrate 301 is turned upside down, and the aboveoperation is repeated on the color filter substrate 301 b. Here,however, the operation is performed differently from when performed onthe TFT substrate 301 a. Specifically, it is performed not only alongthe boundaries V1, V2, . . . (see FIG. 43) between the color filtersubstrate cells 351 b, which are located right opposite to theabove-mentioned boundaries U1, U2, . . . , but also along the boundariesW1, W2, . . . (see FIG. 43) running parallel to and at a predetermineddistance from those boundaries V1, V2, . . . in order to form protrudingportions 351 aa. Thus, the movable unit 410 is moved in one direction(in the direction indicated by the arrow D in FIGS. 31 and 41) from oneedge of the glass substrate 301 to another along the two kinds ofboundaries alternately, in the order V1, W1, V2, W2, . . .

As a result, portions of the color-filter-side polarizer plate 302 b areshaved off by the blade 461, and strip-shaped regions 311 c and 311 d(see FIG. 42) are exposed alternately on the color filter substrate 301b. Subsequently, the wheel cutter 430 is moved along the strip-shapedregions 311 c and 311 d to form scribed lines 312 c and 312 d (see FIG.42).

Thereafter, the glass substrate 301 is rotated through 90° within ahorizontal plane so that the above operation is repeated along theboundaries T1, T2, . . . (see FIG. 43) between the color filtersubstrate cells 351 b, which are located right opposite to theabove-mentioned boundaries Q1, Q2, . . . , to form scribed lines 312 e(see FIG. 43).

Then, as required, a load is applied to the glass substrate 301 to cutit apart along the scribed lines 312 a to 312 e into pairs of a TFTsubstrate cell 351 a and a color filter substrate cell 351 b. At thistime, the portions 354 (hatched in FIG. 42) of the color filtersubstrate 301 b (including the color-filter-side polarizer plate 302 b)located between the scribed lines 312 d and the scribed lines 312 d areremoved as unnecessary portions. This produces, in each pair, theprotruding portion 351 aa in the TFT substrate cell 351 a. Lastly, a COGor FPC is connected to the connection terminals 353 formed on the innersurface of the protruding portion 351 aa to produce the liquid crystalpanel 350 as an end product (see FIG. 24).

In the liquid crystal panel 350 fabricated in this way, the TFT-sidepolarizer plate cell 352 a is so bonded as to cover almost the entireouter surface of the TFT substrate cell 351 a including the protrudingportion 351 aa, and the color-filter-side polarizer plate cell 352 b isso bonded as to cover almost the entire outer surface of the colorfilter substrate cell 351 b.

Moreover, the TFT-side polarizer plate cell 352 a and thecolor-filter-side polarizer plate cell 352 b are so cut as to have, attheir edges 352 aa and 352 ba, inclined surfaces which reflect therising angle of the side cutting edges of the blade 461. Moreover, thewidth with which the TFT substrate cell 351 a and the color filtersubstrate cell 351 b are exposed at the edges on their outer surfaces isequal to about half the width of the bottom cutting edge of the blade461. Accordingly, by adjusting the shape and dimensions of the blade461, it is possible to obtain a structure as described above that offersthe desired mechanical strength of the liquid crystal panel and thedesired resistance to exfoliation of the polarizer plates.

Needless to say, the liquid crystal panel fabricating apparatus 400 ofany other embodiment than the eighteenth embodiment may be used tofabricate the liquid crystal panel 350 by the same procedure asdescribed above.

Incidentally, when a large-format glass substrate is cut apart intoindividual liquid crystal panels in this way, the cutting operationdescribed above needs to be performed in both of the lateral andlongitudinal directions (X and Y directions). Depending on the order inwhich the glass substrate is sectioned, however, the following problemarises. Now, how this problem arises will be described with reference toFIGS. 44 to 48. First, as shown in FIG. 44, when a glass substrate 301having a polarizer plate 302 bonded thereto is sectioned in the Xdirection, a movable unit 410 having a cutting mechanism 460, composedof, for example, a blade 461 to serve as a glass substrate exposingmeans, followed by a wheel cutter 430 is moved in the X direction toshave off and remove the polarizer plate 302 and simultaneously performscribing. Then, at the same time that the polarizer plate 302 is shavedoff to expose a strip-shaped region 311, a scribed line (a crack alongwhich to cut apart) 312 is formed along the mid line on the strip-shapedregion 311. Then, as shown in FIG. 45, the movable unit 410, having theblade 461 followed by the wheel cutter 430, is moved in the Y directionperpendicular to the X direction in the same manner as in the Xdirection to shave off and remove the polarizer plate 302 andsimultaneously perform scribing. In this cutting method, the blade 461is run in front of the wheel cutter 430. This makes it possible to cutapart a glass substrate having a polarizer plate bonded thereto in aperiod of time roughly equal to the time required by a step of simplycutting apart a glass sheet.

However, as shown in FIG. 46, when the blade 461 is moved in the Ydirection perpendicular to the scribed lines 312 formed previously inthe X direction, the cutting edge of the blade 461, which is pressedagainst the strip-shaped region 311 on the glass substrate 301, collidesperpendicularly with the shoulders of the cracks (scribed lines 312)formed by scribing. As a result, as shown in FIG. 47, the liquid crystalpanel may chip at the corners, i.e. at the cross sections between thecutting lines, or, as shown in FIG. 5, the cutting edge of the blade 461may chip 461 a. This shortens the working life of the blade 461, therebyincreasing the running costs, and also degrades the quality of theliquid crystal panel 350. Thus, when the polarizing plate 312 is shavedoff and removed, it is advisable to run the blade 461 in such a way thatit does not cross the scribed lines 312 formed previously.

A cutting method that avoids this problem will be described below withreference to FIGS. 49 to 51. First, as shown in FIG. 49, the wheelcutter 430 for scribing is retracted, and the movable unit 410 is movedin the X direction with only the blade 461 pressed against the glasssubstrate 301. That is, when the movable unit 410 is moved in the Xdirection for the first time, the polarizer plate 302 is shaved andremoved to form a strip-shaped region 311, but no scribed line 312 isformed in this strip-shaped region 311.

Next, as shown in FIG. 50, the polarizer plate is shaved andsimultaneously scribing is performed in the Y direction of the glasssubstrate 301 in the manner described earlier. That is, strip-shapedregions 311 and scribed lines 312 are formed. Here, there are no scribedlines where the polarizer plate 302 is going to be shaved, i.e., in thestrip-shaped regions 311 formed when the movable unit 410 was moved inthe X direction for the first time. Thus, the blade 461 can smoothlyshave the glass substrate 301 without colliding with scribed lines 312.

Lastly, as shown in FIG. 51, with the blade 461 retracted this time,only the wheel cutter 430 is run along the strip-shaped regions 311formed when the movable unit 410 was moved in the X direction for thefirst time so that scribing is performed in the X direction of the glasssubstrate 301 to form scribed lines 312 to achieve cutting. In this way,by performing sectioning in the X direction, then in the Y direction,and then in the X direction in this order, through with increasedoperation time, it is possible to greatly prolong the working line ofthe blade and enhance the quality of the liquid crystal panel.

In a case where more time is allowed, it is also possible to shave thepolarizer plate 302 in the X and Y directions first to form strip-shapedregions 311 in both directions and then perform scribing. Alternatively,it is also possible to separately build an apparatus dedicated to theshaving and removal of the polarizer plate and another dedicated toscribing so that the two processes are performed separately.

INDUSTRIAL APPLICABILITY

Methods and apparatuses for cutting apart a glass substrate, liquidcrystal panels, and apparatuses for fabricating a liquid crystal panelaccording to the present invention are useful in technical fieldsrelated to liquid crystal display devices.

1. A method of cutting apart a glass substrate having a deposited filmformed thereon, comprising the steps of: removing strip-shaped portionsof the deposited film so as to expose strip-shaped regions on thesubstrate; and forming cracks so as to permit the glass substrate to becut apart along the strip-shaped regions exposed thereon by the glasssubstrate exposing means, and cutting the glass substrate apart alongthe cracks.
 2. The method of cutting apart a glass substrate accordingto claim 1, wherein said step of forming cracks so as to permit theglass substrate to be cut apart along the strip-shaped regions exposedthereon comprises the step of forming cracks on the strip-shapedregions.
 3. The method of cutting apart a glass substrate according toclaim 1, wherein said step of forming cracks so as to permit the glasssubstrate to be cut apart along the strip-shaped regions exposed thereoncomprises the steps of forming cracks on a surface of the glasssubstrate opposite to the strip-shaped regions.
 4. The method of cuttingapart a glass substrate according to one of claims 1 to 3, wherein saidstep of forming cracks so as to permit the glass substrate to be cutapart along the strip-shaped regions exposed thereon comprises the stepof forming cracks using a wheel cutter.
 5. The method of cutting apart aglass substrate according to one of claims 1 to 3, including theadditional step of: placing the glass substrate on a workpiece stage,wherein the glass substrate consists of product portions and wasteportions arranged alternately, the product portions being used asproducts after cutting-apart and the waste portions being discardedafter cutting-apart, and, on the workpiece stage, there are formedprojections for supporting the glass substrate at the waste portionsthereof.
 6. The method of cutting apart a glass substrate according toone of claims 1 to 3, wherein said step of removing strip-shapedportions of the deposited film so as to expose strip-shaped regions onthe substrate comprises the steps of shaving off portions of thedeposited film.
 7. The method of cutting apart a glass substrateaccording to claim 6 including the additional step of, determining anangle and a pressing force with which the cutting mechanism shaves thedeposited film according to a thickness and a material of the depositedfilm.
 8. The method of cutting apart a glass substrate according toclaim 6, wherein said step of shaving off portions of the deposited filmcomprises the step of shaving off strip-shaped portions of the depositedfilm using a blade having a cutting edge having a substantiallyV-shaped, arc-shaped, or trapezoidal cross section.
 9. The method ofcutting apart a glass substrate according to claim 8, including theadditional step of determining dimensions of the cross section of thecutting edge of the blade so that the strip-shaped regions are exposedwith a width sufficient to permit the cracks to be formed.
 10. Themethod of cutting apart a glass substrate according to claim 8, whereinsaid step of shaving off strip-shaped portions of the deposited filmusing a blade having a cutting edge comprises the step of using a bladehaving a cutting edge having an opening angle 3° to 6° smaller in aportion thereof away from a tip portion thereof than in the tip portion.11. The method of cutting apart a glass substrate according to claim 8,wherein said step of shaving off strip-shaped portions of the depositedfilm using a blade having a cutting edge comprises the step of using anelongate blade having a same cross-sectional shape throughout a lengththereof.
 12. The method of cutting apart a glass substrate according toclaim 6, wherein said step of removing strip-shaped portions of thedeposited film so as to expose strip-shaped regions on the substratecomprises the step of cutting strip-shaped portions of the depositedfilm with a combination of two cutters fixed together at a predeterminedinterval.
 13. The method of cutting apart a glass substrate according toclaim 12, wherein said step of removing strip-shaped portions of thedeposited film so as to expose strip-shaped regions on the substratecomprises the step of cutting strip-shaped portions of the depositedfilm with a combination of two cutters fixed together at a predeterminedinterval and arranged so that the strip-shaped regions are exposed witha width sufficient to permit the cracks to be formed.
 14. The method ofcutting apart a glass substrate according to claim 6, wherein said stepof removing strip-shaped portions of the deposited film so as to exposestrip-shaped regions on the substrate comprises the step of cuttingstrip-shaped portions of the deposited film with a blade portion thatdirectly shaves off portions of the deposited film and a holder portionthat holds the blade portion.
 15. The method of cutting apart a glasssubstrate according to claim 6, wherein said step of removingstrip-shaped portions of the deposited film so as to expose strip-shapedregions on the substrate comprises the step of applying a predeterminedpressing force to the glass substrate.
 16. The method of cutting apart aglass substrate according to claim 15, wherein said step of applying apredetermined pressing force to the glass substrate comprises the stepof applying an elastic force exerted by an elastic member.
 17. Themethod of cutting apart a glass substrate according to claim 6, wherein,along edges of the glass substrate, there is provided anon-film-deposited portion where the deposited film is not formed. 18.An apparatus for cutting apart a glass substrate, the apparatusincluding a workpiece stage on which a glass substrate having adeposited film formed thereon is placed, securing means for securing theglass substrate in a predetermined position on the workpiece stage,crack forming means for forming cracks on the glass substrate so as topermit the glass substrate to be cut apart along the cracks, andactuating means for moving the crack forming means to a predeterminedposition, the apparatus cutting apart the glass substrate into aplurality of blocks along the cracks, comprising: a glass substrateexposing means for removing strip-shaped portions of the deposited filmso as to expose strip-shaped regions on the glass substrate, wherein thecracks are so formed that the glass substrate is cut apart along thestrip-shaped regions exposed thereon by the glass substrate exposingmeans.
 19. The apparatus for cutting apart a glass substrate accordingto claim 18, wherein the apparatus uses the method of cutting apart aglass substrate according to one of claims 1 to
 3. 20. The apparatus forcutting apart a glass substrate according to claim 18, wherein theapparatus performs both a step of making the glass substrate exposingmeans remove strip-shaped portions of the deposited film and a step ofmaking the crack forming means form cracks on the glass substrate. 21.The apparatus for cutting apart a glass substrate according to claim 18or 20, wherein the actuating means moves the glass substrate exposingmeans and the crack forming means in a same direction.
 22. The apparatusfor cutting apart a glass substrate according to claim 18 or 20, whereinthe glass substrate exposing means and the crack forming means arearranged in a row along a direction in which the actuating means moves.23. The apparatus for cutting apart a glass substrate according to claim18 or 20, wherein the glass substrate exposing means and the crackforming means are integrally held by the actuating means at apredetermined interval, and move parallel to a direction in which theactuating means moves.
 24. The apparatus for cutting apart a glasssubstrate according to claim 23, wherein the predetermined interval isequal to intervals at which the glass substrate is cut apart intostrip-shaped blocks.
 25. The apparatus for cutting apart a glasssubstrate according to claim 18 or 20, further comprising: detectingmeans, controlling means, and guiding means for guiding the glasssubstrate exposing means to a position on a glass surface of the glasssubstrate on which the deposited film is formed.
 26. The apparatus forcutting apart a glass substrate according to claim 25, wherein thedetecting means extends and contracts vertically relative to the glasssubstrate, and has, at a tip thereof, a freely rotatable rolling probeformed of an elastic material.
 27. The apparatus for cutting apart aglass substrate according to claim 26, wherein the detecting meansoperates with a sensing force of 0.2 N (newton) or less.
 28. Theapparatus for cutting apart a glass substrate according to claim 18 or20, wherein the strip-shaped regions and the cracks are formed in agrid-like pattern on the glass substrate.
 29. The apparatus for cuttingapart a glass substrate according to claim 28, wherein the workpiecestage is rotatable through 90°.
 30. The apparatus for cutting apart aglass substrate according to claim 28, wherein the workpiece stage ismovable in a direction perpendicular to a direction in which the crackforming means moves.
 31. The apparatus for cutting apart a glasssubstrate according to claim 18 wherein the crack forming means and theglass substrate exposing means are formed integrally and are togetherrotatable in a plane parallel to a surface of the workpiece stage. 32.The apparatus for cutting apart a glass substrate according to claim 18or 20 further comprising: removing means for removing waste shavings ofthe deposited film produced by the glass substrate exposing means andparticles of the glass substrate produced by the crack forming means.33. The apparatus for cutting apart a glass substrate according to claim32, wherein the removing means is a negative pressure supplying means, apositive pressure supplying means, or a brush-like removing means. 34.The apparatus for cutting apart a glass substrate according to claim 18or 20, wherein the glass substrate exposing means is a cutting mechanismthat shaves off and thereby removes portions of the deposited film, theapparatus further comprising: a fine-adjusting means for guiding a tipof a blade portion of the cutting mechanism to a position on a glasssurface of the glass substrate on which the deposited film is formed.35. The apparatus for cutting apart a glass substrate according to claim18 or 20, wherein an elongate opening is formed in the workpiece stage,the crack forming means being so disposed as to be movable along theopening, the glass substrate exposing means being disposed opposite tothe crack forming means across the glass substrate, the crack formingmeans and the glass substrate exposing means being integrally moved bythe actuating means.
 36. The apparatus for cutting apart a glasssubstrate according to claim 35, wherein the glass substrate exposingmeans is a cutting mechanism that shaves off and thereby removesportions of the deposited film, and has a roller disposed behind itselfwith respect to a traveling direction thereof, the roller being movedtogether with the glass substrate exposing means by the actuating meansso as to roll on the strip-shaped regions on the glass substrate whilepressing the strip-shaped regions, and, when the crack forming meansforms the cracks, the glass substrate is held on the workpiece stage bya composite force of a force with which the securing means secures theglass substrate on the workpiece stage, a force with which the glasssubstrate exposing means presses the glass substrate, and a force withwhich the roller, while rolling, presses the strip-shaped regions. 37.The apparatus for cutting apart a glass substrate according to claim 36,wherein the crack forming means is a wheel cutter, and the roller isformed of a soft material and has substantially same shape anddimensions as the wheel cutter.
 38. A liquid crystal panel composed of apair of substrate cells bonded together with liquid crystal sealed inbetween and with polarizer plates bonded to outer surfaces of thesubstrate cells, wherein at least one end of one of the substrate cellsprotrudes from at least one end of the other of the substrate cells soas to form a protruding portion, connection terminals by way of whichthe liquid crystal panel is driven is formed on an inner surface of theprotruding portion, and the polarizing plate so extends as to cover anouter surface of the protruding portion.
 39. The liquid crystal panelaccording to claim 38, wherein edges of the polarizer plates are located1 mm or less inward from edges of the substrate cells.
 40. A liquidcrystal panel composed of a pair of substrate cells bonded together withliquid crystal sealed in between and with polarizer plates bonded toouter surfaces of the substrate cells, wherein edges of the polarizerplates are so formed as to have a vertical section that becomes thinnerand thinner toward the substrate cells.
 41. The liquid crystal panelaccording to claim 40, wherein the edges are inclined at an angle largerthan 90° but not larger than 135° relative to the outer surfaces of thesubstrate cells.
 42. The liquid crystal panel according to claim 41,wherein removable protective films are laid on outer surfaces of thepolarizer plates so as to be integral therewith.
 43. An apparatus forfabricating a liquid crystal panel, the apparatus fabricating aplurality of the liquid crystal panel according to claim 38 or 40 bycutting apart a glass substrate that has a plurality of pairs, arrangedadjacent to one another, of glass substrate cells bonded together withliquid crystal sealed in between and that has polarizer plates bonded toboth surfaces thereof, comprising: glass substrate exposing means forremoving strip-shaped portions of the polarizer plates so as to exposestrip-shaped regions on the glass substrate; and crack forming means forforming cracks so as to permit the glass substrate to be cut apart alongthe strip-shaped region exposed thereon by the glass substrate exposingmeans, wherein the glass substrate is cut apart along the cracks. 44.The apparatus for fabricating a liquid crystal panel according to claim43, wherein the glass substrate exposing means is a laser radiatingmechanism that irradiates the polarizer plates with a leaser beam. 45.The apparatus for fabricating a liquid crystal panel according to claim44, wherein the crack forming means is a gas spraying mechanism thatsprays a rapid-cooling gas to the strip-shaped region on the glasssubstrate heated by being irradiated with the laser beam.
 46. Theapparatus for fabricating a liquid crystal panel according to claim 43,wherein the glass substrate exposing means is a cutting mechanism thatshaves off and thereby removes portions of the polarizer plates.
 47. Theapparatus for fabricating a liquid crystal panel according to claim 46,wherein the cutting mechanism is composed of a blade that shaves offstrip-shaped portions of the polarizer plates, the blade having acutting edge having a substantially C-shaped, trapezoidal, semicircular,or circular cross section.
 48. The apparatus for fabricating a liquidcrystal panel according to claim 46, wherein the cutting mechanism iscomposed of first and second blades that are arranged so as to face eachother at a predetermined interval and that shaves off strip-shapedportions of the polarizer plates, and a third blade that is arrangedbetween the first and second blades and that scrapes away from the glasssubstrate the strip-shaped portions of the polarizer plates shaved offby the first and second blades.
 49. The apparatus for fabricating aliquid crystal panel according to claim 48, wherein the predeterminedinterval is set in a range of from 1 to 3 mm.
 50. The apparatus forfabricating a liquid crystal panel according to claim 48, wherein thefirst and second blades are a pair of wheel cutters fitted integrallytogether coaxially, each having a cutting edge angle in arrange of from30° to 90°.
 51. The apparatus for fabricating a liquid crystal panelaccording to claim 50, wherein the wheel cutters constituting the firstand second blades have a diameter in a range of from 5 mm to 10 mm. 52.The apparatus for fabricating a liquid crystal panel according to claim48 or 49, wherein the first and second blades are both relativelymovable only in a direction in which they shave the polarizer plates,and are each provided with a plurality of cutting edges having smallerand smaller cutting depths in the direction in which they shave thepolarizer plates.
 53. The apparatus for fabricating a liquid crystalpanel according to claim 48, wherein the first and second blades are soarranged that cutting edges thereof do not make contact with the glasssubstrate.
 54. The apparatus for fabricating a liquid crystal panelaccording to claim 47, wherein the blade constituting the cuttingmechanism has a coating formed thereon so that removed portions of thepolarizer plates do not adhere thereto.
 55. The apparatus forfabricating a liquid crystal panel according to claim 47, wherein thecrack forming means is a wheel cutter.
 56. The apparatus for fabricatinga liquid crystal panel according to claim 55, further comprising: anactivating mechanism for selectively activating the glass substrateexposing means and the crack forming means.
 57. The apparatus forfabricating a liquid crystal panel according to claim 56, wherein theactivating mechanism activates the glass substrate exposing means andthe crack forming means in such an order that a path along which theblade constituting the cutting mechanism travels does not cross thecracks.
 58. The apparatus for fabricating a liquid crystal panelaccording to claim 57, wherein the activating mechanism first activatesonly the glass substrate exposing means to form a first group of thestrip-shaped regions, then activates the glass substrate exposing meansand the crack forming means in a direction perpendicular to the firstgroup of the strip-shaped regions to form a second group of thestrip-shaped regions and a first group of the cracks, and then activatesonly the crack forming means along the first group of the strip-shapedregions to form a second group of the crack.